<正>用地转偏差方法估算在田林网的区域性防风效应，分析了该方法的可靠性和实用价值，并实际计算了苏北沿海防护林网１Ｈ（树高）高度上的防风效应值，得出：①林网的防风效率为１５％～４５％，且对不同风力防风的能力不同，风力越大，被削弱的程度也越大；②不仅林网内部扰动增强，在林网外侧一定范围内也存在一个扰动增强区；③林网对风向的影响有待进一步探讨。

In this paper,the regional protective effects of farmland windbreak network were calculatedwith a geoctrophic deviation method,the reliability was analysed and the value of the method was applied.The value of protective effects of farmland windbreak network at H(the height of tree) was alsocalculated in the northern coastwise of Jiangsu Province.It is found that(1)protective efficiency ofwindbreak network is 15 %～45% and if the wind force is different, the proteCtive ability is distinct:the stronger the wind is,the more the extent of that is weakened;(2)the influence to the wind direction by the windbreak network is not large;(3)not only the perturbation motion strengthens inside thewindbreak network,but also such a region exists to a certain range outside.