The paper firstly describes the structure of the EQ6110HEV hybrid propulsion system. In order to accelerate the developing process of the hybrid propulsion system, an online calibrating/programming software has been simultaneously developed, and five functions of the system are helpful to develop the hybrid propulsion control system rapidly. Secondly, the online calibration system can monitor the state information of the hybrid propulsion system all the time, and modify the parametric maps or update the control programs. Based on the software package, the hybrid propulsion control system is developed and applied to the EQ6110HEV bus. Finally, experiments verify that the online calibration system is feasible and reliable, and can save about 30 per cent of the development time for the EQ6110HEV control system in comparison with that of the standard calibration system.