The RegCM series of climate models are widely used throughout the world and in China. Applications include paleo and present-day climate simulation, mechanistic analyses, studies of atmospheric chemistry and aerosols, and climate change projections. The model is currently developed and maintained at the Abdus Salam International Centre for Theoretical Physics; the latest version is RegCM4. Recently, a long-term simulation was conducted with the corporation of the Institute of Atmospheric Physics of the Chinese Academy of Sciences, the National Climate Center of the China Meteorological Administration, and other institutes, to evaluate its performance in China.