In recent years, with the implementation of the TOU in several provinces, the original user load characteristics have been changed, the peak and valley load differences have been gradually reduced, and the load forecasting in power grid planning has been affected. Therefore, starting from the impact of TOU pricing on grid planning, this paper analyzes the impact of TOU pricing on grid planning and formulates a planning scheme that takes this into account. Secondly, this paper optimizes the TOU price model, analyzes the influence of variable line loss and return risk on the TOU price, and obtains the conclusion that the smaller the load variance is, the less the line variable loss and the return risk are. The optimized model considers the influence of line variable loss and return risk on the economics and applicability of grid planning. The capacity planning and investment in grid planning are modified and optimized to make capacity planning and investment in grid planning more economical, reasonable. At the same time, it is concluded that the maximum load transfer rate is a bridge connecting the TOU price and the power grid planning, and transmitting the impact of TOU price on the power grid planning. Finally, the simulation analysis proves the correctness of the theoretical analysis and quantifies the impact of peak-valley time-of-use price on power grid planning. It proves that the optimization model adopted in this paper has better applicability and accuracy.