Abstract: In view of the low collection and utilization rate of low velocity flow energy, we used numerical simulation and experimental research to study and analyze three different types of shroud, proposed a optimal shroud suitable for micro head, and studied its influence factors. The results showed that the U-shaped shroud had the best comprehensive hydrodynamic performance at low velocity of micro head, and the length of inlet section and the diameter of inlet and outlet had a great influence on the comprehensive hydrodynamic performance of the shroud; the numerical simulation was in good agreement with the experimental results, which provided a reference for the design of shroud of micro head water power generation device.