In order to obtain Aim Precision,according to the parameter requirement of flight test,this paper describes a scheme to gain aim precision through Information fusion based on image measuring and DGPS processing. At the same time it has carried on the theoretical analysis and the calculation steps are given, the test method to estimate accuracy and the tracking accuracy is carried out. Finally the method in engineering application is introduced, it is concluded that the evaluation method in the airborne weapon aiming system accuracy evaluation has certain reference significance. It is good to apply the test technology in the same type flight test.