Exploring the influence law of different photovoltaic penetration rates on the capacity allocation and operation of wind-solar-fire storage systems, a three-layer capacity optimization model considering penetration rate constraints and integrated control of thermal storage is constructed, using a wind-solar-thermal-storage combined generation system as an example. Firstly, introducing the golden search optimization (GSO) algorithm into the solution of capacity optimization configuration, the best capacity configuration of the system under different penetration rate constraints is provided, and the resulting data of system operation indicators is obtained. Then, the obtained results are subjected to a least squares curve fitting, yielding curves depicting the variations of system economics, reliability, and stability with different penetration rates. Finally, the main reasons for the trend changes in the curves are systematically analyzed, providing insights for the optimization and planning of capacity allocation and operation planning of renewable energy systems such as wind and solar.