Abstract: Slope ratio is one of the important factors affecting the hydrodynamic characteristics. Variable-slope flume test was conducted to simulate the slope flow of different water depth, and the influences of 7 different slope ratios on hydrodynamic characteristics were studied. The results showed that the hydraulic gradient, Froude number and Reynolds number of slope flow increase with slope ratio, the resistance coefficient increases with the slope at first and then decreases. For the same slope, it was concluded that Froude number increases with depth at first and then decreases to stable, Reynolds number increases with water depth increase; for 0% ≤J≤1.5%, the hydraulic gradient decreases with water depth at first and then stabilizes; for 2% ≤J≤3%, the hydraulic gradient remains unchanged and then decreases with the increase of water depth.