The invention provides a locally protective sub machine operational control method and a protective system. When the amending of protective sub machine operational parameters is completed, the operational parameters are calculated to amend a first check code for protecting a sub machine, the first check code is sent to other protective sub machines in a ring network, if the first check code detected for protecting the sub machine after the amending of the operational parameters is completed is different from a first check code received by the other protective sub machines, the protective sub machines perform latch-up protection action behaviors. The inconsistency or protective maloperation of the protective action behaviors caused by the inconsistency of the operational parameters for eachprotective sub machine is avoided; the comparison logic of the first check code of the protective sub machine needs to be performed before the protective logic of each protective sub machine operates, the lockout of the whole process from that each protective sub machine begins to amend the operational parameters to that the amending of the operational parameters of all sub machines is completedand efficient in the ring network is ensured, and the lock-up control logic is opened instantly after the amending of the operational parameters of all protective sub machines is completed.