Abstract: The performance of the fast version of the LASG/IAP coupled climate system model named FGOALS_gl in simulating the 20th century air temperature evolution is evaluated and the mechanisms responsible for the evolution are discussed. The overall warming trend and its zonal distribution simulated by the FGOALS_gl is in a good agreement with the observation. Under the natural forcings, such as the solar radiation and volcanic activities, and the anthropogenic forcings, such as greenhouse gases and aerosols, the FGOALS_gl model reasonably simulates the warming trend of the global mean temperature and its decadal variability. Moreover, the FGOALS_gl reproduces the major local warming characteristics over most of the world, expect for the North Atlantic, suggesting that the external forcings significantly contribute to the temperature evolution over most of the world. The main deficiency of the model is that the simulated global warming trend is weaker than the observation. It may be associated with low model sensitivity to the specified greenhouse gases forcing. Generally speaking, the FGOALS_gl model can reasonably reproduce the main characteristics of the 20th century temperature evolution, especially on the global, hemispheric, and continental scale.