Abstract: The giant low-orbit constellation provided low-latency，largecapacity communication channels for user spacecraft such as manned spacecraft，space stations and remote sensing satellites，and there was a resource allocation optimizing problem of satellite beams.The intelligent optimization framework of A2C（advanced actor-critic）using discrete-time deep reinforcement learning was studied，and the beam resource scheduling algorithm that could effectively meet the needs of multi-users，dynamic and concurrent access was formed by combining the concepts of individuals and genes in genetic algorithms.Based on simulation and analysis，the proposed algorithm could be applicable in a variety of typical scenarios.The method could provide effective scheduling results for more than 3000 tasks in 20s，and the task success rate was not less than 91%.The complexity was reduced by algorithm optimization，which could save more than 45% of the time compared with traditional genetic algorithms.At the same time，the convergence problem in the traditional A2C algorithm framework was optimized，which solved the non-convergence problem in the traditional fully connected A2C algorithm.Meanwhile，the convergence speed was increased by more than 38% compared with the DQN（deep q-network）algorithm.

Key words: LEO constellation, beam scheduling, task planning, DRL, A2C algorithm