Deposits induced by huge landslide or debris flow are of big size, hence changing the cross-sectional velocity distribution of channel to a large extent. The aim of this research is to analyze the influence of deposit on the velocity distribution of channel. According to 16 groups of flume experiments (10 on flume bed with gentle slope and 6 on steep slope), the uneven cross-sectional velocity distributions along flow direction caused by different deposit size under gentle slope and steep slope conditions are obtained, and the correction factor of kinetic energy α and the cross-sectional velocity distribution are analyzed. Results show that α well represents the velocity uniformity of cross section. As blockage ratio of deposit increases, velocity distribution becomes more uneven. In particular, as for the channel with gentle slope, velocity distribution reaches the most uneven state at the postion when x/l=0.5; therefore more distance from the upstream of the channel is needed to eliminate deposit’s influence on velocity distribution; whereas for the channel with steep slope, the position with uneven change of velocity distribution is mainly located at the deposit reach, and the peak correction factor of kinetic energy is obviously lower than that of the channel with gentle slope, which has less impact on the upstream and downstream.