Abstract: To ensure that the assembly of each instrument of spacecraft can meet the requirements of the spacecraft's posture and trajectory control, the position of each instrument should be measured. This paper proposes a new measurement method for the invisible points in spacecraft based on laser radar, and a mathematical model for the coordinate system is established with laser radar and the invisible points are measured using a high-precision mirror. The measurement results show that the uncertainty of the test measurement system is within 0.107 1 mm.