Abstract：The formation and development of modern Europe is closely related to the Protestant Reformation that broke out in 1517. During the Reformation, many resists initiated by the populace burst out in many European countries. The contradictions between Feudalism and Capitalism, lords and farmers became more and more accurate. Reformation, to a great extent, shook the foundation of Feudalism and the ruling power of dominant Churches. This religious movement partly finished the darkness and obscurity of the Medieval Europe. After the Reformation, main European countries founded stronger political and economic systems. Reformation stimulates Capitalism, helping the growing of economy, freeing people’s spiritual life, fostering modern science, practicing preliminary democratic theories, and promoting many new trends of thoughts. It’s a necessary event that would happen in the western history. And it’s also a turning point in the Christian and European history. Thus, the study of the causes and impacts of Reformation would catch the glimpses of our incomprehension about the development and core values of Christianity and formation and the development of western culture and history.

Key Words: Christianity；Reformation; cause; impact; society