Drop pit is a kind of bed form developed in rill erosion process,and it is the result from the interaction between rill erosion process and flow characteristics.Six slopes (2°,4°,6°,8°,10°,12°) and five discharges(8,16,24,32,40 L/min) were combined in erosion experiment.Results showed that the average depths of drop pit increased with the increase of slope while average spacing of drop pit decreased.The development coefficient of drop pit increased with the rise of slope,and it was ranged from 1.01 and 1.14 with a positive relationship with SP.With the same slope,the energy dissipation efficiency of drop pit showed a linear decrease trend with the increase of discharge,and it showed a power function increase trend with the rise of slope and SP.The energy dissipation efficiency ranged from 87.28％ and 98.58％.Research results showed that the development and mechanism of drop pit played an important role in flow characteristics and erosion sediment yield.
