Abstract: The measuremem principle of the laser radar and its application in the satellite engine alignment precision test are discussed in this paper. A measuring approach is proposed according to the alignmem precision measuremem requirements for satellite engines. First, a benchmark coordinate frame of the satellite is established by using some target balls at known places. Then, an inner profile point cloud of the engine is obtained by using the hidden point scan function of the high-precision plane mirror. Finally, the directions of the inner key geometry cemer axes arc calculated with the Spatial Analyzer software. The measuremem results show that this method can be used in the alignment precision measurement for satellite engines with high precision and good repeatability.