The rapid development of manufacturing industry making the pursuit of equipment performance increasingly demanding. Proceeded from design, considering testing and diagnosis problems from whole system and life cycle is an effective way to avoid major accidents and reduce the cost of maintenance, therefore, testability is widespread concerned. In this paper, taken marine diesel engine as research object, analyzed its necessity and feasibility of design for testability (DFT), through fully study of marine diesel engine's testability characteristics, introduced multi-signal model to analysis marine diesel engine's lubrication system testability, then advanced improvements for its testability, it can detect and isolate all faults of lubrication system, which provided a reference guide to marine diesel engine's manufacturing.
