Abstract: Li Zhizao is acclaimed as the mainstay of Christianity in China in the late Ming dynasty. He introduced not only religious knowledge but also western scientific knowledge, especially western geometry, into China, when he was affiliated with western missionary. The geometry he introduced not only included the content of Euclid's elements, Archimedes' geometry, but also early western projective geometry and descriptive geometry. Therefore, his work emulated that of Xu Guagqi.