The fuel injection ring is an important part of the micro-turbojet engine. The uniformity of fuel injection quantity determines the uniformity of the temperature field in the combustion chamber. At this stage for micro-turbojet injection ring uneven fuel injection problems，This paper intends to compensate for the influence of pressure loss through the use of unequal-diameter needle structure to ensure the uniformity of injection quantity. By using CFX software to simulate the experiment of three-dimensional flow field inside the fuel injection ring, And calculates the outlet flow rate, outlet velocity and the pressure change of the entire internal flow field of injection needle on the injection ring body, and finally compares with the experimental results; Based on this simulation method, the results show that the scheme of unequal injection nozzle can improve the problem of nonuniform injection of fuel injection ring. According to the calculated results, we can lay the foundation for the study of the internal flow field of the injection ring and make the analysis.