To make a quick and effective organic phosphorus pesticide detection in the agricultural production, a detection system for Organophosphorus Pesticides based on USB is designed in the paper. Firstly, the theory of organic phosphorus pesticide detection system is briefly introduced. Then ARM microcontroller is used to finish the data acquisition, and it communicates with the computer by USB to comply real-time transmission of data between the master computer and the slaver computer. And finally the function of the detection system for Organophosphorus Pesticides is realized.