In recent years,due to the frequent changes in global climate,the frequency and strength of typhoon,as well as the extremely weather disasters have terrified. At the same time,forests are suffered tremendous damages. Wind pressure,speed and turbulence intensity generated by typhoon are applied to trees in forest,causing wind strength fall frequently. Therefore,it is of great significance to investigate the wind resistance of trees. In this study, the numerical method of computer simulation was used to analyze the movement of the flow field in the forest. The main methods were as follows: firstly,the three-dimensional canopy was modeled and meshed by GAMBIT,and then the standard k-epsilon equations were used to simulate the flow field of three-dimensional canopy. Finally,the distributions of the pressure,wind speed,and turbulent intensity were calculated by the simulated calculation. The results showed that,for a single tree,when the crown's porosity changed from 0.25 to 0.75,the leaf area index (ILAI) varied from 2.77 to 0.58,and the wind speed fluctuation within the canopy decreased from 8.0 m/s to 4.0 m/s.The fluctuation range of the internal pressure dropped from 229.0 Pa to 143.5 Pa,and the fluctuation of turbulence intensity dropped from 6.03% to 3.40%. For three tree crowns constituting a forest canopy,when the porosity changed from 0.25 to 0.75,the ILAI changed from 2.77 to 0.58. At the same time,the wind speed difference before and after canopies changed from 17.67 m/s to 15.89 m/s, the pressure difference was changed from 180.38 Pa to 117.38 Pa,and the range of turbulence intensity was changed from 4.0% to 2.4%. As the large pressure difference between the front and the rear of the canopy and the large wind speed difference in the canopy would cause the structure of the tree to be destroyed, it can be seen that the sparser canopy was,the better the wind resistance performance could be obtained.