Abstract: The present disclosure discloses a call transfer method and a communication system, and the call transfer method includes: transferring, by a source CTI platform, a call of a user terminal processed by a source traffic resource device to a target traffic resource device upon a call hang and transfer request of the source traffic resource device, and setting the source traffic resource device in a suspended state according to a call processing response message provided from a target CTI platform; and receiving a call release notification message sent from the target CTI platform after the target traffic resource device processes the call, setting the source traffic resource device in an active state according to the call release notification message, and transferring the call of the user terminal back to the source traffic resource device.