Abstract: Based on provincial panel data of 30 provinces（cities and autonomous regions）from 2003 to 2013, this paper built two panel threshold models which took the intensity of pesticide use and crop biodiversity as threshold variables and analyzedthe threshold effect of the intensity of pesticide use and crop biodiversity on the occurrence acreage of crop diseases and insect pests. The results showed that the intensity of pesticide use could not only increase the occurrence acreage of crop diseases and insect pests, but also had a significant threshold effect on crop biodiversity. When the crop biodiversity was lower than the threshold value, an extra unit of the intensity of pesticide use would increase 0.8048 units of the occurrence acreage of crop diseases and insect pests; when the crop biodiversity was higher than the threshold value, the impact of the intensity of pesticide use on the occurrence acreage of crop diseases and insect pests would decrease to 0.66 times of its lower threshold value. Crop biodiversity had a significant threshold effect on the occurrence acreage of crop diseases and insect pests, and it was double thresholds: when the intensity of pesticide use was lower than the first threshold value, crop biodiversity had a significantly negative effect on the occurrence acreage of crop diseases and insect pests; when the intensity of pesticide use was between the first and the second threshold values, the effect of crop biodiversity on the occurrence acreage of crop diseases and insect pests was negative but not significant; when the intensity of pesticide use was higher than the second threshold value, the effect of crop biodiversity on the occurrence acreage of crop diseases and insect pests would be more significant than it was lower than the first threshold value. As a result, this paper put forward the following suggestions: controlling the intensity of pesticide use and strengthening the protection of crop biodiversity.