This paper is in the light of the backwardness of test means , over - complication in operation and inaccessibilily to the test of the system main performance parameters in the case of arny equipping Helmet Mounted Sight ( HMS) , and extensive researches are conducted on improvement and home manufacture of HMS in No. xx project , to solve the actual problem of maintenance in the army , give a full insight into the principle of HMS and effectively better the utilization and maintenance of military equipment and study on the HMS test system.