Method, device and system for backspacing voice calls to circuit switching domain

The invention discloses a method for backspacing voice calls to a circuit switching (CS) domain. The method includes receiving service request information including voice call and called number information of the CS domain from caller UE (user equipment) and commanding an ENB (effective noise bandwidth) to launch CSFB (circuit switching fall-back) switching; receiving switching request information containing information required by CS from the ENB, selecting an MSC (mobile switching center) and transmitting PS (packet switching) to CS request information containing information and called number required by CS to the MSC, and enabling the MSC to call the called UE; receiving PS to CS answer information fed by the MSC, transmitting switching command information to the caller UE through the ENB so that the caller UE can access to the 2G/3G (second generation/third generation) network, wherein the PS to CS answer information contains CS resource information prepared by target BSS/RNS (base station subsystem/radio network subsystem), and the switching command information also contains resource information prepared by the target BSS/RNS. The invention further provides a device and a system for backspacing voice calls to the circuit switching domain. By the method, the device and the system for backspacing voice calls to the circuit switching domain, connection time delay can be shortened.