Embodiments of the present invention provide a machine-to-machine communications privacy protection method and system, a machine-to-machine communications service management entity, and a related device. The method includes: after receiving a location access message, determining, by a service management entity and according to locating information, an entity that performs privacy inspection; and triggering, by the service management entity, the entity that performs privacy inspection to perform privacy inspection. The M2M service management entity determines in advance the entity that performs privacy inspection and triggers the entity that performs privacy inspection to perform privacy inspection. Therefore, with the method provided in the present invention, message interaction on an mId interface is reduced, thereby reducing a message overhead. In this way, a network load is reduced, and especially for a wireless network with an air interface, benefit that reduction of a signaling overhead brings is greater.