The increase of photovoltaic capacity will lead to the small signal stability problem of the system. The generalized short circuit ratio index can be used to describe the small signal stability of the multi-photovoltaic feed-in system. Based on this, a maximum admission capacity optimization method for any node in the multi-photovoltaic feed-in AC network under the generalized short circuit ratio constraint is proposed. Firstly, the small signal stability analysis model of multi-photovoltaic feed-in system was established. Secondly, the generalized short circuit ratio was expressed in the form of unreduced extended impedance matrix. Considering the situation of any node in the photovoltaic access network, the maximum access capacity optimization model of photovoltaic based on generalized short circuit ratio constraint was established, and the improved particle swarm optimization algorithm was used to solve the model. Finally, the correctness of the method was verified by simulation.