[Objective] To provide technical support for measuring the overland flow depth rapiclly and accurately. [Methods] The overland flow depth was measured with ultrasonic method under different slope gradients and flow rates. At the same time the flow depth was measured with the digital display probe method and dye tracing method. Based on the measurement results of digital display probe method or dye tracing method, four indexes including mean absolute error(MAE), mean relative error(MRE), the relative mean square error(RRMSE ), and Nash-Sultcliffe efficiency coefficient(NSE) were calculated to analyze the similarity of the three methods. [Results] The depths measured by ultrasonic method were closer to the reference values and had a high degree of correlation with other two methods. [Conclusion] The ultrasonic method could be used to measure the depth of overland flow quickly and effectively in un-eroding bed experiments in laboratory for the studies of hydrodynamics properties of overland flow and soil erosion mechanism.