Aiming at the problem of frequency oscillation caused by the output fluctuation and load variation of renewable energy in the microgrid, a load frequency controller with hybrid H2/H∞ robust control strategy is proposed. Firstly, a load frequency control model of wind-photovoltaic-diesel microgrid with power disturbance signal is established. Then a robust H2/H∞ controller is designed based on robust H∞ theory. In the design of the controller, the salp swarm algorithm (SSA) is used to optimize the relevant weighting matrix parameters and norm weights to achieve the best adjustment performance of the controller. Finally, the simulation results show that compared with the traditional robust H∞ control and PID control, the proposed H2/H∞ robust controller has better control performance under the external power disturbance of the microgrid and the parameter disturbance of the system.