With more and more extensive application of spatial geometric precision measurement technology in the manufacturing and assembly process of equipment manufacturing industry, angle measurement is developing from plane angle to spatial angle. The spatial angle of the different planes of the magneto-optical trap is measured. A parallel flat crystal is utilized as the standard plane to draw the normal vector of the surface to be measured. The spatial angle is effectively divided into two plane angles, which are the horizontal projection angle and the vertical projection angle. The traceability of the spatial angle is guaranteed, and the maximum spatial angle deviation between the normal vectors of the measured surfaces of the magneto-optical trap is 0. 286 0 mrad. Then, the measurement uncertainty of this method is evaluated as 0. 095 9 mrad by the Monte Carlo method. Compared with the coordinate measuring machine method, the maximum deviation is 0. 184 2 mrad. When the flatness index of the surface is set to ± 0. 145 4 mrad, the consistency between the two is good. At present, this method has been applied in the development of the physical vacuum subsystem of the NIM5 cesium atomic fountain clock, which proves that the method can meet the accuracy requirements of the measurement.