Before the birth of modern science, for ancient astronomers in the East and the West, without the theoretical arm of modern science and the law of universal gravitation, it would not be successful to explore the principle of celestial motion. Ancient Greek scholars used the deduction method of geometric system to imagine the specific shape of celestial bodies to predict their positions, but why those imaginary crystal balls or the subsequent round of uniform wheel rotation were attributed to the driving force of the running heaven. As for where the power that moved heaven came from, it can't be explained, and it can only be attributed to God. Ancient astronomers in China obtained a lot of data through observation, and designed a set of algebraic calculation methods based on these data, with the purpose of predicting the position of celestial bodies. The reason for their movement is attributed to the action of qi. "All actions should be angry." ("Jin Shu? Compared with the spirit of materialism, the views of ancient astronomers in China also contain the elements of materialism. They all explain the motion of celestial bodies in their own way, and the result can only be approximate to some extent, or even a form of speculation, which is determined by the nature of ancient science. How can we say that the geometric model vividly describes the trajectory of celestial bodies, but we don't know that similar results have been obtained through mathematical calculation? Both star map and catalog can describe the position of celestial bodies, and both geometric drawing method and analytical method can find the middle vertical line of a line segment. Different methods have the same result. How can we promote this and suppress that? In fact, many tables and calculation methods in China ancient calendar can be explained by geometry. Japanese professors Kenichi Nakauchi and Liu Jinyi explained the calculation methods of the distance between the sun and the moon and the intersection point in China calendar by geometric method and algebraic method respectively, and the results were consistent.