Abstract: A new radiation scheme is included into the general circulation model (SAMIL-R42L26) of the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics/Institute of Atmospheric Physics (LASG/IAP). Compared with the previous radiation scheme (SES1), spectral interval, gas absorption, computation efficiency etc. have been improved in the new radiation scheme (SES2), so the radiative flux simulated by SES2 is improved correspondingly. In clearsky conditions, the biases of long wave flux at the top of the atmosphere (TOA), short wave flux absorbed by atmosphere, and the incident short wave flux at surface are reduced a lot especially in convection active regions. In cloud-sky conditions, the biases of radiative flux are also reduced to some extent. However, there still exist large biases, which are closely related to the poor performance of the cumulus convective parameterization. Hence, we include a new cumulus convective parameterization into the SAMIL R42L26 to further improve the simulation results. It is shown that water vapor content is greatly increased along the equator and the strong “double ITCZ” is eliminated with the new convective scheme. At the same time, the biases of radiative flux are reduced significantly along the equatorial convergence zone. The clear-sky long wave flux at TOA, the incident short wave flux over the oceans, and the global mean energy budget at TOA are closer to the observations. Our study also shows that there are still some biases in the radiative flux simulation, which might be related to the aerosol effect, the land surface process, and the cloud physics. These are to be investigated in the future.