To improve efficiency of engines，according to the characters of a novel series parallel hybrid electric bus(SPHEB) to define the operation area of ice，a kind of power balancing control strategy is adopted and the battery power is used as a variable to optimize the efficiency of fuel converter，and the PI control is implemented to control the SOC balance. To validate the proposed strategy’s effectiveness and reasonableness，a forward model is built based on simulink and the simulation results demonstrate that the proposed strategy can successfully improve the efficiency of fuel economy up to 6.74% compared with that of equivalent fuel minimum control strategy，while the battery SOC is also limited in the desired range.