China was geographically isolated through much of its early history. Before the Silk Road connected it to other parts of the world in about 200 BCE, the Gobi desert and certain mountain ranges (including the Himalayas) kept it separate from other societies. Few wanted to venture across such forbidding terrain.
Because the groups the early Chinese were most in contact with consisted of nomadic herders who lived very simple lives and usually could not read or write, the Chinese developed the idea that they themselves were an innately superior culture, a concept that persisted even after contact with other, more advanced civilizations.
Left by themselves because of their geography, the Chinese pooled resources and developed technologies. They developed ways to produce high-quality silk, porcelain, and paper. When the Silk Road and more contact with other civilizations occurred, the Chinese were well positioned to profit from trade and build a powerful culture. Their silk and porcelain became highly coveted by those whose own cultures lacked the technology or resources to produce such fine wares.