In view that underwater measurement device on lead fish has high power consumption and low precision of artificial water depth measurement by cable way, and that current meter on the lead fish cannot measure the flow direction or determine the position of the lead fish, we developed an intelligent system of lead fish hydrological information measurement. The system adopts ultra-low power circuit to increase the working hours of the device, and three-dimensional posture circuit to measure the three dimensional position of the lead fish in real time. Moreover, it could improve the precision of flow velocity measurement and obtain flow direction by using the Kalman data fusion algorithm. It could also improve the precision of water depth measurement by combining surge wave sensors with real-time circuit to address the influence of waves on depth measurement.