Abstract: With increasing penetration ratio of new energy in the power system, a large number of power electronic converters with different control modes are connected to the power system, which forms a heterogeneous and hybrid system. The interaction between the converter and the grid-impedance causes a series of small-signal instability phenomena, which threatens the operation safety of the novel power system. Therefore, a single input and single output(SISO) impedance model of the grid-forming(GFM) energy storage and grid-following(GFL) PV hybrid power generation system is built. Based on the positive-net-damping criterion, impacts of different control modes in grid-tied converter, operation modes of GFM energy storage and grid strengths on the damping features and stability of the hybrid system are studied. The research results indicate that the GFM energy storage can enhance the stability of hybrid system under the weak grid condition but decrease system’s stability under strong grid condition. As a result, the accessed location of GFM energy storage converter should be reasonably selected. Finally, simulation results by Matlab/Simulink validate the correctness of the theoretical analysis.