Abstract: According to the international methods of pest risk analysis and characteristics of urban forestry in Beijing,a quantitative risk assessment system in Beijing for the main non-indigenous pests was proposed.This system was used to analyze three non-indigenous species, Dendroctonus valens,Hyphantria cunea and Apriona swainsoni. The results show that the risk of these three species in the Beijing area is 2.46, 2.30 and 2.02, all highly risky. Based on the result and extensive risk communications combined with the management experience of the Beijing Forest Protection Station, the authors proposed that effective control measures are adopted to prevent these three pests from entering Beijing area.