Katniss Everdeen is able to survive the Hunger Games because of a few factors. First, with the help of her team and Peeta, she is able to capture the emotions of the audience. She and Peeta are able to create a compelling backstory. They portray themselves as star crossed lovers who find themselves pitted against each other in the games. When the games begin, Katniss and Peeta find themselves on opposing sides, but Katniss tends to Peeta when he is ill, and is willing to risk her life to save his. This further captures the interest of the audience. That is why President Snow has no choice but to allow Peeta and Katniss to both survive the games. Originally, he changed the rules to allow two contestants from the same district to survive. When Katniss and Peeta defeated their last opponent, he wanted to change the rules back. Katniss and Peeta threatened to commit suicide (by ingesting poison berries and depriving the capital of its victor). In the end, Snow allows Katniss and Peeta to both win the Hunger Games.
There are several reasons that Katniss Everdeen survives the games. Katniss takes the place of her younger sister, Prim, because she knows her sister can't win. Katniss herself doesn't really care about winning, she just doesn't want her sister to have to enter.
Katniss comes from a district that is not very well off. She knows what it is like to have to hunt and can do with very little. She and Peeta form a bond during the games, as well. She remembers Peeta giving her bread for her family when she was younger. She uses her skills with the bow and arrow, and her skill of hunting. She is incredibly intelligent, as well. When the powers that be decide to change the rules, where there can only be one winner from the district, Katniss outsmarts them.
"If Peeta and I were both to die, or they thought we were...My fingers fumble with the pouch on my belt, freeing it. Peeta sees it and his hand clamps on my wrist. "No, I won't let you." "Trust me" I whisper. He holds my gaze for a long moment then lets go. I loosen the top of the pouch and pour a few spoonfuls of berries into his palm. Then I fill my own. "On the count of three?" Peeta leans down and kisses me once, very gently. "The count of three," he says. We stand, our backs pressed together, our empty hands locked tight. "Hold them out. I want everyone to see," he says. I spread out my fingers, and the dark berries glisten in the sun. I give Peeta's hand on last squeeze as a signal, as a good-bye, and we begin counting. "One" maybe I'm wrong. "Two" maybe they don't care if we both die. "Three!" It's too late to change my mind. I lift my hand to my mouth taking one last look at the world. The berries have just passed my lips when the trumpets begin to blare. The frantic voice of Claudius Templesmith shouts above them. "Stop! Stop! Ladies and gentlemen, I am pleased to present the victors of the 74th Hunger Games, Katniss Everdeen and Peeta Mellark! I give you the tributes of District 12!"
Katniss uses her wits and physical aptitude to survive the games. She and Peeta relied on each other and in the end it paid off.
Katnisss was able to survive the Hunger Games becuase of what she did with Peeta Mellark nearing the end of the games when both of them were the only ones left. Coming from the same district, Katniss remembers how when she was younger, Peeta saw her practically starving on the streets and he decided to give her some burnt bread that his mom told him to throw out. This allowed a bond to form between the two giving them trust with each other. During the games, it was announced that if two people were to survive until the end who came from the same district, they could both be eligible to win the games without killing each other. But, at the end when both Katniss and Peeta survived until the end of the games with only each other, the gamemakers decide to change the rules and have them fight against each other. Refusing to do so, Katniss and Peeta decide to intake some lethal berries which will kill both of them making the game pointless because there will be NO victor at all. Right as Katniss and Peeta were about to put the berries in their mouths the gamemakers reconsider and decide to change the rules back to what it was before so that both of them could survive and win the game.
Katniss uses her greatest strength, her wit, to survive the Hunger Games. When she teams up with peeta this also helps her because when becoming "star crossed lovers", the districts erupt with this new scandal. Soon their story turns into a real love story and do anything to protect each other. Katniss and Peeta both threatened to commit suicide which would leave no victor in the Hunger Games. Therefore, President Snow had no choice but to let them survive.
Katniss survives on two bets - first, the bet that the Capitol and the Gamemakers need to crown a victor (or, as she hopes, a pair of victors) rather than show citizens the final two dead bodies; second, the bet that Peeta trusts her completely to risk death with her. As such, Katniss and Peeta both put the poisonous berries into their mouths. Katniss is proven correct when the Gamemakers hurriedly crown both individuals as victors in the hopes that they do not actually ingest the berries. We know that Katniss intended for this to be the result and that Peeta inherently understood her plan, as neither one of them actually chewed or swallowed and were able to spit out the berries quickly.