With the development of grid-load intelligent interaction, the connection between grid side and load side has gradually deepened. Based on grid-load interaction, this paper sets the power shortage and load shedding rounds by integrating grid frequency and voltage. Since the traditional intelligent algorithms have slow convergence speed and fall into local optimal solution easily, an improved firefly algorithm is proposed to improve the search speed and global optimization ability. And on this basis, an optimized load shedding strategy with the goal of minimizing the actual load shedding is proposed. This strategy takes into account constraints such as grid real-time frequency and voltage, which can effectively improve the lean level of emergency control of the grid load. Finally taking the actual grid in a certain area as an example, the simulation results show that this proposed strategy can effectively improve the speed and accuracy of the load shedding action in emergency situations, and ensure the safe and stable operation of the grid.