The invention relates to a method for testing the key performance of a drive shaft assembly of a constant velocity universal joint in the technical field of automobile part test. The method comprises: (1) automobile steering equivalent testing: using a Hermite interpolation method to locate a critical point, judging the boundary value of neighborhood of the critical point by a cubic interpolationpolynomial, thereby realizing the testing on high precision swing moment and swing angle properties; (2) equivalent testing on integrated relationship of mobile terminal universal joint displacement,swing angle and sliding force: using an inflection point subdivision sampling method and an optimal square approximation method to carry out fitting on the boundary value of the neighborhood of an inflection point by a Legendre polynomial operator, thereby realizing the testing on the integrated relationship of the displacement, the swing angle and the sliding force; and (3) power transmission stability equivalent testing: using a LOG operator to carry out precise edge localization of the boundary position,and using an optimal uniform approximation method to carry out fitting on the boundary property value in the domain of the critical point, thereby realizing the testing on assembly clearance property. In the invention, high precision automatic detection technology and algorithm are usedto test multiple key performance indexes, thereby effectively reflecting the performance property of tested products.