Abstract: During the intermediate maintenance of LM2500+ gas generators, the heavy spots of high-pressure compressor and high-pressure turbine may be installed in the same direction, which will lead to excessive vibration due to rotor imbalance during commissioning. However, the dynamic balancing method adopted for such model of generators would consume much fuel and take a long time. In order to reduce the cost of dynamic balancing operation during commissioning and improve the work efficiency, the traditional commissioning environment was transformed by installing a reflective tape on the rotor as the keyphasor identifier, and adding the keyphasor acquisition equipment and signal processing equipment suitable for this model, so that the keyphasor and vibration signals could fuse with each other and the phase data could be obtained for dynamic balancing by vector based method. The example tests during commissioning show that the installed relevant equipment can meet the needs of data acquisition and processing. Besides, the dynamic balancing by vector based method can effectively reduce the number of start-up tests and the consumption of material and manpower, thus ensuring the successful commissioning. In the future, the improved method could be extended to the site of compressor station of long-distance natural gas pipeline and other similar workplaces, so as to provide reference for the dynamic balancing of LM2500+ gas generator in different environments.