General verification rules or calibration specifications only check and calibrate the comprehensive errors or hardware indicators of portable coordinate measuring instruments, but do not verify the correctness of their software functions and algorithms. According to the requirement of management and control in practical work, this paper analyzes the importance and difficulty of software verification and validation, and puts forward a simple and easy-to-operate software validation method based on algorithm comparison and equipment comparison, which is suitable for internal measurement and testing organizations in enterprises. The validation process and validation results are described concretely through a software validation example of laser tracker.