There is a contradiction between high processing complexity and limited processing resources when turbo codes are used on the on-board processing(OBP)satellite platform.To solve this problem,this paper proposes a partial iterative decode method for on-board application,in which satellite only carries out limited number of iteration according to the on-board processing resource limitation and the throughput capacity requirements.In this method,the soft information of parity bits,which is not obtained individually in conventional turbo decoder,is encoded and forwarded along with those of information bits.To save downlink transmit power,the soft information is limited and normalized before forwarding.The iteration number and limiter parameters are optimized with the help of EXIT chart and numerical analysis,respectively.Simulation results show that the proposed method can effectively decrease the complexity of onboard processing while achieve most of the decoding gain.. There is a contradiction between high processing complexity and limited processing resources when turbo codes are used on the on-board processing (OBP) satellite platform. To solve this problem, this paper proposes a partial iterative decode method for on-board application, in satellite only carries out limited number of iteration according to the on-board processing resource limitation and the throughput capacity requirements. In this method, the soft information of parity bits, which is not achieved individually in conventional turbo decoder, is encoded and forwarded along with with those of information bits. To save downlink transmit power, the soft information is limited and normalized before forwarding. The iteration number and limiter parameters are optimized with the help of EXIT chart and numerical analysis, respectively. Simulation results show that the proposed method can effectively decrease the complexity of onboard processing while achieving the most of the decoding gain