该文首次提出了林下植物喜湿度参数ＭＬＰ（ＭｏｉｓｔｕｒｅＬｏｖｉｎｇＰａｒａｍｅｔｅｒ），并用包括ＭＬＰ在内的１４个林分因子与松毛虫危害程度进行逐步回归分析，从中筛选出主林层郁闭度、海拔高度、油松平均胸径和林下植物喜湿度参数４个关键因子，与松毛虫危害程度之间均呈显著的负相关关系，并进一步用这４个因子与松毛虫危害程度建立多元线性回归模型，该模型可对松毛虫危害程度进行风险评估 In this paper, we proposed the MoistureLovingParameter (MLP) for understory plants for the first time. Based on the stepwise regression analysis of 14 stand factors including MLP and the damage degree of the pine caterpillars, Height, the average breast diameter of Pinus tabulaeformis and hygroscopicity parameter of understory plants, and the degree of damage to Plutella xylostella were significantly negatively correlated with each other, and the multiple linear regression models were further established by using these four factors and the damage degree of Plutella xylostella This model provides a risk assessment of the damage to pine caterpillars