Abstract: In order to determine the shearing properties of crop stalks conveniently and accurately, a portable manual/electricity controlled shear tester was developed. In this system, the AC motor or spring was used as actuators, an embedded system based on STM32 MCU was used as control platform, and a pull pressure transducer was used to collect pressure?signal. The pressure curves or other experimental results can be displayed in terminal and stored in SD card in real time, the work and maximum values could also be calculated concurrently. The experimental results showed that this system was credible and?stable, and the accuracy reached 0.84%.This system can meet the requirement of shearing force detection and is convenient to the study of mechanical characteristics for crop stalks.