Abstract:In order to meet requirement of aircraft assembly with large size, high precision and measurement points scattered, compared the advantages and disadvantages, measurement accuracy and application scenarios with 3 kinds of portable coordinate measuring equipment?. this paper take the laser tracker as an example to explain the main factors affecting the measurement process of flexible assembly, such as the accuracy of laser tracker and its accessories, personnel, environment fluctuations, measurement methods, etc, and take some suggestion for control. Controlling the above influencing factors within an acceptable range can improve the quality of measurement results and ensure the measurement accuracy.