Heterogeneous distributed real-time simulation system is a special kind of real-time system. This paper solves its fault-tolerant problem based on the CSP (checkpoint-based spare processor) model, which is an improvement of the traditional SP (spare processor) model with checkpoint mechanism. Firstly, two propositions are put forward based on the characters of simulation system. Secondly, the Worst Case Response Time of the simulation tasks are analyzed based on Markov chains and the schedulability analysis rules for simulation task are presented. In the end of the paper, a fault-tolerant scheduling algorithm CSP-RTFT is proposed and simulated. The results show that the algorithm can achieve better stability, higher task accept ratio than SP-RTFT which is based on SP model, whereas the resource utilization ratio is lower than those based on PB model.