Disclosed are a heterogeneous network switching method, device and system, relating to the technique of communication. When a network-side device such as a base station determines that a UE needs to be switched into a non-3GPP network, switch signaling carrying switch indication information is sent to the UE; the switch indication information is used for instructing the UE to switch some of or all of the bearers from a 3GPP network to a non-3GPP network, so that the UE can switch some of all of the bearers from a 3GPP network to a non-3GPP network according to the switch indication information, thus realizing heterogeneous network switching initiated by a network side.