The definition, synopsis and development of climate model and simulation is sum-marzed in this paper. The basic feature of several types of model, such as energy-equilibrium model, radiative-convective model, general circulation model (GCM). random model and so on, are described. Twoexamples, i. e. the experiment of atmospheric warming due to increasing CO2 by using GCM and the studyo nc lima tic chan ge and predictability with the mechanism model, is given in order to explain two major approaches of the climate simulation at present.