In order to analyze the performance of threshing and separating unit with multi cylinder，the paper introduced the design on the test bed of threshing and separating unit with multi cylinder，which based on the modularization design and combined into a variety of forms of threshing and separating unit. At the same time，with industrial computer and acquisition cards as control center，a measurement and control software were programmed to collect，display and analyze data of motional parameters such as rotational speed，torque and power consumption，et al. Transverse axial threshing and separating unit with three cylinder were tested in the threshing and separating unit with multi cylinder. The whole process of threshing and separating unit with multi cylinder was simulated and reproduced. 