The embodiment of the invention provides an unlocking method and system of an arrival protection section. On the basis of the active request for unlocking the arrival protection section of a computerinterlock (CI), when the CI cannot receive a stop signal due to reasons of a trail or other reasons and the arrival protection section cannot be locked, the arrival protection section can still be unlocked and the availability of communication base train control (CBTC) is improved. Moreover, even in the running process of the train, the arrival protection section can be unlocked, and the availability of CBTC is further improved.