A comparison study was made of the modeling results from a series of models to calculate the climatic impact of greenhouse effect, especially, its impact on the climate of China was studied. Meanwhile, the possible natural climatic change in the next 50 years was also considered, which depends mainly on the long-term changes of solar irradiance and volcanism. It is shown that the cooling associated with the natural climatic variability may compensate to some extent the warming caused by the strong increment of greenhouse effect. However, the greenhouse effect will gradually predominate over the two factors above mentioned after 2010 AD. Global mean temperature may rise over 0.6℃ in the 2030s in comparison with the annual mean of 1961~1990. It is possible that the temperature increment in East Asia will be greater than that averaged for the globe. Annual precipitation will be increased in general over East Asia, but summer drought may be intensified in the northern China with increasing of evaporation and decreasing of rainfall.