Abstract: The longitudinal drivability is degraded seriously when the full hybrid electric drivetrain with single motor switches from the pure electric drive mode to the hybrid drive mode. To address this problem, a phased coordination control strategy of power source and clutch is proposed in this paper. Firstly, a control-oriented dynamic model is established. And then, according to the operating status of engine and clutch, the whole mode transition process is divided into four stages. Based on the feed forward and feedback control method, the pashed coordination control strategy is designed to adjust the speed or torque of power source and clutch in each phase. Finally, the effectiveness of the control strategy is verified by simulation comparison and bench test. The proposed coordinated control strategy can effectively improve the longitudinal drivability of the full hybrid electric drivetrain with single motor during mode transition, and also can reduce the wear of the clutch.