Abstract: The numbers of citrus psyllid on the host plants in decreasing order were as follow: Murraya paniculata, young and adult citrus trees. The high temperature in summer (mean temperature, over 28℃and maximum one, over 37℃), dry in autumn (relative humidity, around 70%) , and the increase of population of Tamarixia radiata after September restrain the growth of citrus psylla. But, this pest maybe break out when the tender shoots formed in the crown of host plants, mean temperature in 10-day duration is 25-27℃ and relative humidity is 77-83%. In this period pesticide should be sprayed to control effectively the epidemic of citrus Huanglungbin.