A method for a service to occupy protection resources in shared protection, comprising: when receiving a command or service state information, a node responding the command or the service state to allocate protection resources to an appropriate service according to priorities of commands and service states from high to low in the order of: high-level manual command, service signal failure, service signal degradation, and low-level manual command; the node determining priorities of signal failure of different services according to service levels and then determining the subsequent priorities of signal degradation of different services according to service levels; the high-level manual command comprises a lock command and a force switching command, the lock command comprises from high to low priority: lockout of protection, lockout of protection segment and lockout of signal, wherein the lockout of protection refers to preventing all signals from occupying the protection resources, the lockout of protection segment refers to preventing all signals from occupying cross-segment resources, and the lock out of signal refers to preventing the signal from occupying the protection resources; the force switching command comprises from high to low priority: force switching to working command and force switching to protection command, the low-level manual command comprises from high to low priority: manual switching command, exercise signal, response, no reply returned, and no request, after allocating the protection resources to the appropriate service, the node still maintaining states of working service, wherein: a trigger condition for the working service switching from the failure state -> failure state is that some or all of the protection resources of the working service are locked or fail; the trigger condition of failure state -> switching state is that part or all of the protection resources lock is cleared, the failure disappears or the protection resources are released by services with higher priorities; the trigger condition of switching state -> failure state is that all the protection resources are locked, fail or are occupied by services with higher priorities; the trigger condition of switching state -> switching state is that some of the protection resources are locked, fail or are occupied by services with higher priorities. when receiving a command or service state information, a node responding the command or the service state to allocate protection resources to an appropriate service according to priorities of commands and service states from high to low in the order of: high-level manual command, service signal failure, service signal degradation, and low-level manual command; the node determining priorities of signal failure of different services according to service levels and then determining the subsequent priorities of signal degradation of different services according to service levels; the high-level manual command comprises a lock command and a force switching command, the lock command comprises from high to low priority: lockout of protection, lockout of protection segment and lockout of signal, wherein the lockout of protection refers to preventing all signals from occupying the protection resources, the lockout of protection segment refers to preventing all signals from occupying cross-segment resources, and the lock out of signal refers to preventing the signal from occupying the protection resources; the force switching command comprises from high to low priority: force switching to working command and force switching to protection command, the low-level manual command comprises from high to low priority: manual switching command, exercise signal, response, no reply returned, and no request, after allocating the protection resources to the appropriate service, the node still maintaining states of working service, wherein: a trigger condition for the working service switching from the failure state -> failure state is that some or all of the protection resources of the working service are locked or fail; the trigger condition of failure state -> switching state is that part or all of the protection resources lock is cleared, the failure disappears or the protection resources are released by services with higher priorities; the trigger condition of switching state -> failure state is that all the protection resources are locked, fail or are occupied by services with higher priorities; the trigger condition of switching state -> switching state is that some of the protection resources are locked, fail or are occupied by services with higher priorities. a trigger condition for the working service switching from the failure state -> failure state is that some or all of the protection resources of the working service are locked or fail; the trigger condition of failure state -> switching state is that part or all of the protection resources lock is cleared, the failure disappears or the protection resources are released by services with higher priorities; the trigger condition of switching state -> failure state is that all the protection resources are locked, fail or are occupied by services with higher priorities; the trigger condition of switching state -> switching state is that some of the protection resources are locked, fail or are occupied by services with higher priorities.