Method and system for formally analyzing motion planning of a robotic arm based on conformal geometric algebra. The method includes determining specific structural and motion planning parameters of a robot, establishing a corresponding geometric model for the basic components and motion planning constraints of the robot based on a conformal geometric algebra theory, the established geometric model being described in a higher-order logic language, performing formal modeling for a motion process of the robot based on the established geometric model to obtain a logic model of the geometric relations involved in the motion process of the robot, obtaining a motion logic relationship corresponding to a constraint or attribute of a motion process to be verified of the robot, and verifying whether the motion logic relationship is correct. The method and system are used for analysis to improve the accuracy of the verification and reduce the complexity of the computations.