Abstract: In order to find out the optimum flow of hydraulic pipe-conveying vehicle of charged bucket, model test and theoretical analysis were employed to analyze the hydraulic characteristics of the pipe under different flow conditions. The analysis results show that the greater the flow in the pipe is, the greater the piezometric head is for a specific pipe section; for the same section, the greater the flow velocity is, the faster the vehicle is, and the earlier the vehicle passes through, the earlier the piezometric head changes. The variations of flow velocity do not affect the decrease trend of the piezometric head along the pipe no matter where the section is, but the decrease magnitude is different. However, the transport efficiency of the pipe first increases and then decreases with the increase of flow velocity.