The invention discloses a region distance protection system based on a self-adaptive blocking region, which comprises a fault identification module, a topology identification module, a communication module and a region distance module, wherein the fault identification module identifies fault of each electrical components in a substation and outputs the fault to the topology identification module; the topology identification module identifies a blocking region corresponding to protection of each line interval region distance in a self-adaptive mode, and region locking signals corresponding to each line interval region distance are formed; the communication module transmits locking signals of each line interval region outputted by the local topology identification module to a substation at the opposite side of each line interval, receives region locking signals transmitted by the substation at the opposite side of each line interval and outputs the signals to the region distance module of each line interval at the side; and the region distance module is used for identifying the line fault. The region distance protection configuration work is simplified, the system is applicable to changes of various operation modes, the engineering implementation efficiency is improved, and the overall power supply reliability of the power grid is ensured.