The invention provides a physical layer optimization simulation method and system for a power grid information physical system. The method comprises: collecting operation parameters of a power grid; initializing a pre-established power grid information physical system physical layer simulation model based on the operation parameters; simulating by adopting a time-varying phasor method based on theinitialized power grid information physical system physical layer simulation model; wherein the power grid information physical system physical layer simulation model comprises a power electronic interface equipment alternating-current and direct-current converter model established by adopting a mean value model technology. According to the method and the system, a mean value model method is provided for a power electronic interface equipment alternating current-direct current converter with a complex model to simplify the model, a physical layer modeling method is optimized, a time-varying phasor simulation method is also adopted to carry out large-scale power transmission and distribution hybrid network time-varying phasor simulation, and the physical side simulation speed is greatly improved.