The overlap region of the parallel light beams in a space is analyzed when a dynamic precision target is running. The region is considered to be a cusiform cone region which can be defined accurately. When a dynamic precision target is used to test an optoelectronic device, it only needs to let the azimuthal pitch visual axis intersection point of the device to be tested be in this region. The dynamic precision target is used to test the angle and tracking accuracy of a given optoelectronic device in different positions in the region for many times. The maximum standard deviation and mean deviation of the test data obtained are much less than the corresponding specifications of the given device. The test result shows that as long as the azimuthal pitch visual axis intersection point of the device to be tested is in the above region, the test error due to the position deviation of the device to be tested is extremely limited. The test result has low discrete degree and good repeatability. It can meet the requirements for practical application. The verification test validates the definition of the fusiform cone. It shows that this definition can be taken as the theoretical basis for judging whether the device to be tested is in alignment with the rotating target during test.