To explore the temperature distribution in the simple plastic greenhouse of south China, a model was established including component of inner and outer space, inside plant and soil layer, etc. Based on analysis of solar radiation and heat exchange between different components, 3-D steady simulation of temperature distribution was carried out in greenhouse. The Monte Carlo model was adopted in thermal radiation and transfer process, shear stress transport (SST) model was used in air turbulence analysis, and the crop was simplified as continuum. The result showed that the value of simulation was a bit higher than that of the measurement. The absolute error was below 2.2℃ and relative error was 6.7%. The airflow had an obvious effect on temperature distribution and fluctuation, and the temperature of inlet side was lower than that of outlet side. It seems feasible to consider the crop as continuum in simulation model in this case, while the simulation value showed a bit higher. 