The embodiment of the invention discloses an access unlocking method and device. The method comprises the steps of judging whether a resource conflict train enters an access proximity section or not after a closed state of an access entrance signal machine is received, if yes, searching for the operation state of the resource conflict train, judging whether the resource conflict train can stop stably in front of an access entrance according to the operation state, and judging whether other trains enter the access section or not if the resource conflict train can stop stably in front of the access entrance; if no other trains enter the access section, a current access is unlocked, specifically, the operation state comprises the position and operation speed of the resource conflict train. When it is determined that the train can stop stably in front of the access entrance by searching for the operation state of the train, and it is also determined that no other trains enter the access section, the current access is unlocked immediately, safety can be ensured, the access unlocking time and handling time for other accesses are shortened, and the operation efficiency of a mobile blocked train control system is improved.