Angle measurement is widely used in industrial manufacture and military fields. The research progress of large spacing spatial angle measurement technology is introduced,and the typical measuring equipments are analyzed. A dynamic angle measurement method based on machine vision is presented. It uses the high precision two-axis servo system to identify and track the cross landmarks in the distant scene. Real-time image processing algorithm is used to calculate and track offset,and then they are passed to the two axis servo system for correction. The precision detection of the weapon system is realized by constructing the transfer model of angle coordinate system between the target and the angle measurement sensor. The method can be used for optronic mast offset and artillery barrel rocking amount detection,and it has the characteristics of high precision,low cost and suitable for large spacing spatial angle measurement under field conditions.