The problem of difficult task allocation in unmanned combat systems composed of heterogeneous multi unmanned platforms has been addressed by focusing on the construction of a mathematical model for task allocation. Firstly, analyze the operational scenarios and capabilities of the modified system; Then, mathematical definitions were given from aspects such as goals, tasks, unmanned platforms, and battlefield environments, and corresponding mathematical model functions were provided; Finally, the optimization objective function and constraints for system task allocation were provided, and the particle swarm optimization algorithm was used to solve the instance constructed based on the task allocation model. The calculation results verified the rationality of the task allocation model construction.