Abstract: Forty permanent plots were selected at Kunyushan Forest Ecological Positioning Station, and taking the population density of Kunyushan web-spinning sawfly (Cephalcia kunyushanica) to represent the damage level of insect pest, the differences in mean DBH increment of Japanese red pine (Pinus densiflora) trees during the period of 2006—2008 on various plots and the growth difference of P. densiflora trees suffered from continuous feeding or intermittent feeding were analyzed and compared. Based on the results, the local and overall impact of C. kunyushanica's attack on P. densiflora stands were evaluated. The results showed that after continuous or intermittent feeding, there were significant differences in shoot length, and the difference in growth rate was also very significant. It was found that the growth of current year shoot was not affected by current year feeding while was affected by last year’s feeding. Current year shoot suffered significant length reduction when it had previously experienced high intensities of two successive attacks last year and the year before last. However, the DBH increment in various stands suffered from different sawfly populations showed no significant difference. This indicated that infestations of sawfly may have obvious impact on shoot growth in a short term while it might have little affection on persistence of whole pine stands. Thus, it is difficult to judge the affection of sawfly infestation on pine stands only by pine shoot growth in a short time.