In view of the difficulty found in the hybrid power supply of the virtual synchronous generators (VSG) and the synchronous generators, it is necessary to clarify the differences between the dynamic performance of the VSG and the synchronous generators. Firstly, the control principle of VSG has been introduced, with the mathematical model established. Meanwhile, on the basis of mathematical derivation, an analysis has been made of the dynamic performance of inverters and synchronous generators from two aspects of inertia power and frequency dynamic response. According to the different dynamic characteristics, the VSG control parameters are re-tuned according to the frequency response time and power oscillation degree, thus reducing the dynamic characteristics difference between the two. Finally, it is pointed out that the moment of inertia required by VSG is different under different operating conditions. By adjusting the control parameters, the dynamic characteristics of VSG controlled inverters are closer to that of synchronous motors, even characterized with a better performance than that of the synchronous generators.