According to the main pin four wheel alignment angle error problem in the verification process,a new type of automatic verification device of four wheel alignment based on multi degree of freedom space tangent mechanism is developed. The main pin of the verification device after the tilt adjustment simulation movement and main pin inclination can independently accomplish the work step by step,the main pin movement due to interference angle error are avoided. On this basis of this device and based on the space geometry analysis,the model of four wheel alignment main pin inclination verification is established. Through the analysis and derivation of the geometric relationship of the model,the main factors affecting the accuracy of the kingpin inclination angle are obtained. According to the national standard,the accuracy of the main pin back angle and the main pin inclination value are detected,the result is conformed to the national standard. The design will provide reference for the design of the four wheel alignment device verification.