In order to further improve overall heating efficiency of the greenhouse heating system, a hot air heating system which used the biomass boiler as a heat source and the fan coil as the end of the cooling device was presented. Combined with experiment greenhouse, a CFD model about this greenhouse without plants was set up. After that, a CFD simulation was carried out by using this CFD model. After compared with the simulation results and experimental data, it was found that the overall trend of the temperature in the greenhouse was consistent. Error of each point was less than 3℃, and the root mean square error was 0.66℃. The results indicated that the CFD model was effective. The results showed that the forced-air heating system could effectively improve the indoor temperature. The temperature range of plant growth area was 12～17℃. The plant canopy temperature was evenly distributed without larger gradient.