In this paper,the shift principle of mechanical transmission without torque interrupt is analyzed,and a dynamic model describing the shift process is established. Then,a shift strategy for the transmission under discussion is proposed based on the prearranged control of clutch torque capacity. Moreover,a simulation model of the transmission is set up with the Matlab /Simulink software. Finally,for the purpose of optimizing the shift quality in terms of jerk and slipping work,the control parameters of throttle opening during the shifting is calculated by using the the simplex method and the genetic algorithm. Simulated results indicate that,with the adoption of the designed control strategy and the optimized control parameters,both the shift shock and the clutch slip during the shifting are successfully controlled,and a continuous and smooth power output is thus secured.