Based on the current situation that China is still not equipped with the ability to maintain and test the airframe/engine data processing unit and with the current failure rate of this unit, this paper puts forward a maintenance test platform based on virtual instrument technology. The hardware design is completed based on the GPIB instrument and the VXI model. The labview driver module is utilized to realize the control of various test instruments and further accomplish the software design. An error analysis of this platform is carried out and as indicated by the analysis result, this system testing possesses a relatively high precision. With all the parameter errors within the scope of performance indicators, the system is able to satisfy the maintenance and testing demand of airframe/engine NC unit.