Abstract: With the continuous improvement of installed capacity of new energy sources, the rotating reserve capacity and moment of inertia in the power system are relatively reduced, which poses a severe challenge to the safe and stable operation of the power grid. The virtual synchronous generator (VSG) technology can simulate the conventional thermal power units from the external characteristics and has the ability of active frequency regulation, active voltage regulation and damping system oscillation. The widespread application of the technology provides a solution to the problems caused by the high proportion of new energy access to the power grid. To ensure the stable operation of grid-connected VSG is a prerequisite for application of this technology. In the current literature, the stability of VSG is mainly studied in micro-grid or single grid-connected VSG. However, the stability of multiple grid-connected VSGs still lacked the research. In addition, the current research does not analyze the influence on the stability of the system when multiple VSGs have different parameters. In this paper, the method of small signal stability analysis is used to analyze the grid-connected stability of parallel connection of multiple VSGs. Firstly, based on the circuit topology and control strategy of multiple VSGs to the power grid, a small signal model of multiple VSGs is established, and the correctness of the small signal model is verified by simulation. Secondly, through the sensitivity analysis of eigenvalues of small signal model, the dominant eigenvalues of multiple VSGs system are identified. On this basis, the influence of the VSG control parameters (active droop coefficient, virtual inertia, etc.) and the power grid parameters (line resistance ratio, line length, etc.) to characteristic roots and stability of the system are discussed under the two operating conditions with the same parameters and different parameters of VSGs. Through the analysis of the critical stability parameters of multiple VSGs system and single VSG system, the stability difference of multiple grid-connected VSGs system and single grid-connected VSG system was further compared. Finally, the simulation results verify the correctness of the results. The research shows that when the control parameters and grid parameters of multi-parallel grid-connected VSGs are the same, the grid-connected stability is basically the same as that of single grid-connected VSG system. When the active droop coefficient of VSG is too small or the virtual inertia is too large, it may cause the parallel VSGs to oscillate in the same frequency and in the same phase. The critical stability parameter of the multiple VSGs is the same as that of the single VSG. When the control parameters and grid parameters of multiple VSGs are not the same, there is a significant difference in the system oscillation mode between the multiple VSGs and single VSG. In this case, when the control parameter of one VSG is not stable, a low-frequency oscillation of this VSG occurs firstly, then other VSGs with stable parameters will oscillate with the same frequency, but the amplitude and phase of the oscillation have obvious differences with that of single VSG.