The speed of screw pump motor used for crushing tomatoes in corresponding paste plant influences the quality of its processing seriously. Therefore, based on Profibus-DP, we proposed a control method in order to actually operate the screw pump motor for real-time monitoring with a touched PC and PLC screen. Moreover, the frequency converter was used as actuators system solutions, and the operation was analyzed according to the debugging steps. The results showed that the system characterized by good stability and fast response could run a good monitoring of screw pump motor as well as get real-time feedback of running and alarm information. The application of this system ensured that the speed of screw pump motor was accurately controlled, and the digital management of system was realized. This might help to extend the service life of the screw pump and save electricity. Our results here could provide a new clue for similar automatic control of processing equipment on agricultural processing.