Abstract: This paper proposes a satellite carrier resource allocation method to meet the requirements of business QoS guarantee and communication reliability for improving spectrum efficiency under the condition of dedicated satellite communication resources. Firstly, based on the Shannon channel capacity formula, the minimum value required for Eb/N0 under the limit rate transmission time is derived. Then, according to the reliability requirements of power grid business communication, the difference between spectral efficiency and optimal communication performance is equivalently converted. Then, based on the QoS guarantee priority of power grid collection services, the minimum signal bandwidth B and communication time window are allocated to different priority collection services, thereby achieving an improvement in the spectral efficiency of satellite carrier resources. Simulation results show that the proposed method can effectively improve spectral efficiency.