Metal Cutting is one of the main processing methods in the field of aviation manufacturing, and strain and strain rate have a great impact on the chip formation and surface quality. The monitor and control of the strain and strain rate can contribute to the study of the cutting mechanism and conditioning of the machining process. In this paper, we developed an experimental setup for monitoring and controlling of strain rate in the primary shear zone. An in-situ imaging platform of orthogonal cutting is built, which can acquire the images of shear zone in the orthogonal cutting process. A global DIC algorithm accelerated by multithreading is developed to improve the efficiency of image analysis. The image analysis and strain rate calculation can be conducted as well by the DIC software. An online adjustment of spindle controlled by computer is established, which can adjust the spindle magnification in real time according to the relationship between the measured strain rate and the target strain rate. Two experiments for the control of the strain rate in the primary shear zone during orthogonal cutting are carried out. The experimental results show that this system can monitor and control the strain rate in the shear zone with an error less than 10% compared with target value, and less than 23% compared with theoretical predicted value.