Rhytidodus poplara Li et Yan is a new insect pest on poplar. The morphology, biology and occurrence and its natural enemies were introduced. It has three generations a year in Shanghe, Shangdong Province and overwinters as adult in defoliation and weeds. It comes to feed on poplar in middle February, then mates and lays eggs on leafstalk. The fecundity per female is 113～361 eggs. The egg stage lasts for 10～23 days and the larval for 17～43 days. The adult life_span is 7～69 days. The female lays eggs in  5～12 days after emergence, usually from the afternoon to evening. The eggs were in the leafstalk. The important natural enemies includes Anteon yani and nagrus  sp.