For meeting the need of new type aircraft assembly detection, proposed an assembly detection new method based on laser radar, which uses laser radar to measure the positioning reference of assembly components, analyze the measurement data and extract the key size information. The method solved the assembly problem fundamentally. This paper combined with the assembly testing instance of certain component on an aircraft, solved the out of tolerance of size coordination in the process of aircraft assembly. The results prove that the digital assembly detection technology based on laser radar can detect the assembly problem effectively. The new method is of great significance to realize the digital automatic aircraft assembly.