The invention discloses a circuit domain fall back processing method and a circuit domain fall back processing device. The method comprises the steps as follow: A mobile management entity (MME) receives a context release request message sent by a first terminal when the first terminal falls back to a circuit domain communication system; the MME judges whether the first terminal transmits data in a grouped domain communication system, and if yes, stores connection information of the first terminal in the grouped domain communication system. According to the method and the device provided by the invention, continuity of data transmission in the grouped domain communication system can be maintained after the terminal falls back to the circuit domain.