The invention discloses an online satellite system communication resource allocation method oriented to a hybrid task. The method mainly solves the problem that the relay satellite system communication resource cannot be dynamically distributed in the prior art. The realization process is as follows: a relay satellite system real-time acquires a task request, and independently allocates the dynamic updating of a planning period realization resource for each antenna through a multi-antenna asynchronous scheduling mechanism, thereby capturing the burstiness of the task; in each planning period,a communication resource conflict graph is constructed to describe the communication resource conflict of the relay satellite system, and a communication resource allocation scheme is generated by solving the maximum independent set of the communication resource conflict graph, and the communication resource of the relay satellite system is allocated according to this scheme. The composing efficiency on the hybrid task is improved through the multi-antenna synchronous scheduling mechanism, the conflict between the communication resources is represented by using the communication resource conflict graph, the complexity of the communication resource allocation is reduced, and the utilization efficiency of the communication resource is improved.