Abstract: With the high proportion of renewable energy access, how to allocate energy such as wind power, hydropower, and thermal power faces many problems. Aiming at the problems of low speed and precision of the heuristic search algorithm in multi-energy joint scheduling, a joint dispatching model of wind-hydro-thermal power based on mixed-integer linear programming is proposed. Firstly, relaxation variables are introduced into the model constraints, the constraints in the model are transformed into standard constraints. By selecting new base variables to replace the original base variables, the size of the feasible region is continuously compressed in the iterative process. Finally, the optimal solution is solved. Compared with other optimization algorithms in operation time and fitness value, the effectiveness of the algorithm is verified. In the simulation, the improved IEEE 24 bus test system is used for verification, through the simulation of 15 thermal power units, 3 wind farms, and 3 hydropower stations under different conditions, the causes of the impact of coal-fired cost and output fluctuation of thermal power units are analyzed. The experimental results show that there are obvious differences in the output fluctuation of hydropower regulated wind power and thermal power under different conditions, It provides an optimization strategy for including wind-hydro-thermal combined dispatching model in different situations.