In order to fully understand the role of climatevegetation feedbacks on different timescales, dynamic vegetation models need to be incorporated directly within climate models. By introducing the dynamic vegetation model VEGAS (VEgetationGlobal AtmosphereSoil), a new IAP atmospherevegetation coupled model IAP9L_VEGAS has been developed. The results from the new coupled model show that the model can reasonably simulate the vegetationecosystems productivities, and the vegetation and soil carbon pools and their annual cycles. Furthermore, IAP9L_VEGAS well reproduces the global observed leaf area index (LAI) distributions. Result comparisons between the new coupled model and IAP9L show that the LAI over the rainforests of South America and Africa simulated by IAP9L_VEGAS is more than 3.5 higher, and much closer to the observed. The precipitation and near surface air temperature simulated by IAP9L_VEGAS is closer to the observed.