【Background】 The papaya mealybug Paracoccus marginatus Williams and Granara de Willink, a native species in Central America, is an important agricultural and forestry pest. Since 2008, the species has invaded many countries of South and Southeast Asia and caused huge economic losses, and it was recently found in Taiwan and Guangzhou. 【Method】 Based on information about biology, ecology and the distribution of P.marginatus, this paper introduced its morphology, host plants, geographic distribution, damage and biological characteristic. The potential geographic distribution for P.marginatus was analyzed by using an ecological niche model (Maxent) and ArcGIS with the occurrence records of the pest all over the world. 【Result】 The forecasted results indicated that P.marginatus could survive in huge area in the south of the Yangtze River. Climate and food in South China were very suitable for the survival and hazard of papaya mealybug. 【Conclusion and significance】 Risk analysis of P.marginatus showed the pest might pose a serious threat to papaya and cassava of South China, and it was very important to quarantine and monitor the invasion of this pest.