Abstract: Mathmatic model of regenerative brake for single shaft parallel hybrid electric vehicle (PHEV) was established and a series-parallel multi-brake pedal was correspondingly designed. To ensure the brake stability, a new brake torque distribution similar to the atomic transition was proposed. The factors of generator efficiency, battery charging efficiency and braking stability, which restrict the increase in regenerative efficiency, were analyzed and the sequential quadratic programming(SQP) algorithm was used to optimize the gear decision and regenerative brake torque ouput. The model of hybrid propulsion system has been built under the Cruise and Matlab/Simulink joint simulation platforms. According to the rule of UDC drive cycle simulation, the experimental data indicate that, compared with traditional dual parameters shift decision, the final state of charge (SOC) could be increased by 1.5% and the regenerative efficiency be 11.00% more than that in the normal brake pattern. Three typical cycle road tests have been implemented and the results well fit in with the simulation ones.