Abstract: Using the data of observed temperature and wind profile, and surface sensible heat flux in July and December 1986 in Beijing District, comparing with the results from water tank simulation experiment, the theoretical models for predicting the development of convective mixed-layer are assessed. It is obtained that the entrainment coefficient used in zero order jump model (slabmodel) are 0.15 and 0.10 in Summer and Winter, respectively, and 0.20 for the laboratory experiment. With regards to the first-order jump model the entrainment coefficient becomes stable with the value between 0.15-0.19 except in the initial convective developing stage of the mix-layer.