Abstract: Through field model experiments and simulation methods; the shelterbelt porosity of shelter lattice for the China farmland plains was discussed in the paper. The results showed that the best shelterbelt porosity was between 0.3 and 0.5, the optimum porosity for the farmland protection was 0.35. The results also indicated that, if the vector composition simulation of wind speed was applied, it would be useful for the designing and planning of shelterbelts.