In view of the low reliability of the accessories of aero-engine in service, the problems that exist in the developing procedure and their causes are analyzed in this paper. According to the relational requirement of the National Military Standard, and considering the conventional structure, function character of the aero-engine accessories, the missionized/simulated operational test and the individual tests, which are not explicitly stipulated in the specification, and recently added test requirements of reliability maintenance are discussed on emphasis. The general requirements of the tests for newly developed engine accessories are proposed, and the typical example is given. This paper has instructive and paradigmatic meanings for the work of the accessory reliability of the new developed aero-engine, programming the approval test, and determining the project.