Based on the samplecircle method and the 2×2 contingency table of species presence/absence data collected from 50 permanent plots in Kunyushan region, the VR analysis, χ²test, association coefficient, Ochiai association index, Dice association index, point correlation coefficient, Cramer index, and percentage cooccurrence were used in quantitative analysis of the interspecific correlation of Kunyushan webspinning sawfly (Cephalcia kunyushanica, a defoliator) occurrence and adjacent understory plants of natural forests in Kunyushan region. The results indicated that there was a significant positive correlation of overall association existing among Cephalcia kunyushanica and 195 neighboring shrub or herbage plants (P<0.01). The result of χ²test showed a positive association for 83 speciespairs and a negative association for 112 speciespairs. The ratio of negative pairs was higher than positive ones. Furthermore, the insect showed extremely significant positive interspecific correlation relations to 11 species including Carex rigescens, while negative ones to 16 species including Carex siderosticta respectively (P<0.01).