In this paper, a multi-user, multi-task and multi-server scenario for low earth orbit (LEO) satellite edge computing system is established, and a joint optimization algorithm for computation offloading and resource allocation based on deep deterministic policy gradient (DDPG) is proposed, which solves the problems of computation offloading and resource allocation requiring high dimensional state space and high dimensional continuous action space, significantly improves the system utility values and achieves excellent convergence effect