Assembly performance test bed is an indispensable equipment in the development and production of air compressor assembly. The test bed studied is a mechanical, electronic and hydraulic integrated equipment and its measuring and controlling system mainly consist of computer system, process channel, control object and measuring and controlling software. Guided by the “soft hardware” design conception, two “soft” subsystems was adopted in a one-level computer system to replace the generally adopted two-level “hard” system consisting of measuring and controlling subsystem and management subsystem. This improvement allows the more applications of integrated sensor and intelligent controller, resulting in a simpler hardware and greater openness. The practice indicated that, with rapid parameter adjustment, accurate measuring, large testing scope and high automation, the system meets all the technical indexes of test requirement.