In this paper, the spatial distribution pattern of Adoxophyes honmai larvae was analyzed with aggregation indexes, Taylor’s power law and Iwao’s distribution function. The results showed that the spatial distribution pattern of Adoxophyes honmai larvae belonged to aggregation with the form of colony, which means the larvae attracted each other, and the basic component of the distribution was individual colony, with the aggregation intensity increased with the density. It was tested by Blackith’s method, when m < 1.0095, the aggregation was caused by some environmental factors; when m >1.0095, the aggregation was caused by their behavior and environmental conditions. Based on this distribution pattern, a suitable sampling number (N =1.96²/D² [1.23602/ m +1.27954]) and Iwao’s model (T₀ ( n) = 3.6 n ± 8.9888 n^1/2) of sequential sampling were put forward. The largest sampling number was 234.