There are several conflicts within this story.
First, the narrator who comes to visit the Usher house has an internal conflict. He is conflicted because he wants to help his friend Roderick Usher, but he is also disturbed by his friend's state of mind and the strange occurrences in the home. Despite his good intentions (the narrator's), he is still frightened and, at times, apprehensive. He does the best he can, however, to help entertain his friend Roderick Usher.
Another conflict would be one between Roderick Usher and the narrator. This conflict is related to the previous one. The narrator has not seen his childhood friend in a very long time, so he knows very little about the person he has become. When he learns more about what Roderick has become and the person he is and the struggles he faces, he is clearly disturbed and worried, even somewhat perplexed. He wants to help his friend, but he is not quite sure how to do so. He tries to convince himself that there is nothing supernatural occurring in the home to cause his friend's mental state, but the evidence of this not being the case overwhelms him, particularly at the end of the story:
Although he [the narrator] tries to tell the reader that Roderick's anxiety and nervousness are simply symptoms of the latter's mental anguish, the narrator, and therefore the reader, becomes increasingly disturbed as the story progresses. (" 'The Fall of the House of Usher'" Style")
Another conflict could involve the Usher family's heritage and its own survival. It is implied that the Usher family has inbred, which has caused problems such as mental illness within the family. Roderick and his sister are the only remaining Usher family members. Their line dies with them.