Angle movement of directional tube may cause the initial disturbance in the launching process of multiple rocket launching systems (MRLS), and then affects the precision of movement. In view of this situation, a dynamic non-contact measuring method is proposed. In this paper the system composition is introduced, the calculation model of angle motion parameters is given, which is based on the description method of space attitude with PRY angle and homogeneous transformation, and the information extraction of light spots and the data processing are elaborated. This method is proved to be stable and reliable with high precision by means of the original rational test with three-dimensional modeling software, and it can be used in rocket weapons tests.