Abstract: To investigate the occurrence and distribution of the pest Frankliniella occidentalis of midwest region of Inner Mongolia, field investigation and laboratory identification method were used to identify and investigate the pest.The results showed that through the investigation and identification of different sites and host plants in the central and western regions of Inner Mongolia, it was found that the distribution of Frankliniella occidentcdis in midwest region of Inner Mongolia was quite extensive and complicated.Morphological characters of Frankliniella occidentalis were described and the occurrence and discribution and host plants of this quarantine pest in midwest region of Inner Mongolia were introduced and summaried the danmage and control methods.