According to the specific technical requirements for tests of single-jet nozzles of aero engine's performance, this paper introduces the application of computer measurement and control technology in a testing device for single-jet nozzles of aero engine, as well as the construction and working principle of its hardware and software, is presented in this paper. Several key aspects of the design and processing methods are also discussed, including how to precisely control the pressure value of the fuel at the inlet of the nozzles, and how to calculate the spray angle and Un-uniformity with high stability and consistency by using the image recognition technology. Finally the usage of the testing device is introduced briefly.