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, this paper proposes a maximum admission capacity optimization method for any node in the multi-photovoltaic feed-in AC network under the generalized short circuit ratio constraint. Firstly, the small signal stability analysis model of multi-photovoltaic feed-in system is established. Secondly, the generalized short circuit ratio is 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 is established, and the improved particle swarm optimization algorithm is used to solve the model. Finally, the correctness of the method is verified by simulation.