Abstract: When the screw pump works,the power is transferred to the pump dipped in the well by the polished and sucker rod from the ground,so the load and torque borne by the rod should reflect the working condition of the production system.Firstly,we make a testing system to monitor the load and torque on the rod at a real time.Then we analyze the corresponding relation between the testing data and the working condition of the production system.From the result of diagnosis,we can see this theory is quite true and the successful rate can reach to 90%.At last,we make a program of the working condition diagnosis based on this diagnosis theory.