According to the multi-machine time scale simulation method suitable for the multi-machine fault-tolerant architecture of the attitude and orbit control system, independent and mutually exclusive data spaces are designed in a shared memory of multiple machines, a data basis is provided for unified management of time scales, a mode of multiple times of time scale synchronization is adopted, the data exchange and transmission process in the shared memory of the multiple machines is subjected to stage division, multiple machines are in a synchronous state in different data processing stages, non-synchronous data are prevented from being introduced into calculation, task-level multi-machine time scale unification is achieved, then a synchronous controller is designed, the synchronous controller is used for communicating with all the machines, synchronization is carried out with simulation time as a control reference, high-priority synchronous parameters are designed, the single-machine debugging process and the multi-machine time mark unification are no longer contradictory, and the system-level multi-machine time mark unification is realized. Finally, the problem of multi-machine time scale unification under a fault-tolerant architecture is solved, the simulation method not only realizes task-level time scale unification, but also realizes system-level time scale unification, and is successfully applied in a space station simulation environment at present.