A resource release control method, a communication system, and a device are configured to delete a bearer context on an original-side heterogeneous-system management network element (NE) even if a target-side management NE does not support interaction with a serving gateway (S-GW) and does not support an idle mode signaling reduction (ISR) mechanism. The resource release control method includes: acquiring version information of a target-side management NE, when a user equipment (UE) activating an ISR mechanism is handed over from an original-side network to a target-side network; and deleting a bearer of an original-side heterogeneous-system management NE, if the version information indicates that the target-side management NE does not interact with an S-GW and does not support the ISR mechanism. Meanwhile, a communication system and a relevant device are also provided.