Abstract: Panonychus citri were treated with pyridaben in laboratory. The results showed that the resistance ratio of the pest to the acaricide reached 34.96-fold after 12-generations treatment. The resistant strain displayed cross-resistance to omethoate、amitraz、cyhalothtin、isocarbophos and propargite. The mechanism studies showed that resistance to pyridaben was mainly associated with the increasing activities of glutathione transferase、mixed-function oxidases and Acetylcholinesterase.