小麦红吸浆虫的幼虫和圆茧在土壤中均呈聚集分布，前者随虫口密度的增高其聚集强度增强，后者则随虫口密度的增高趋于均匀。应用ＩｗａｏＭ＊－Ｍ回归法求得理论抽样数模型，从而导出在一定置信概率七、允许误差Ｄ和不同虫口密度下的理论抽样数Ｎ。采用Ｉｗａｏ提出的序贯抽样法得到幼虫的序贯抽样型。 The larva and cocoon of Synechocystis sp. Were aggregated and distributed in the soil. The former increased with the density of the insect population and the latter increased with the density of the insect population. Applying the IwaoM * -M regression method to obtain the theoretical sampling number model, the theoretical sampling number N at a certain confidence probability of seven, the allowable error of D and different population density of insects is derived. Sequential sampling method of larvae was adopted by Iwao’s sequential sampling method.