According to the measured data of the reach between the Pangxieqi and the Huoyanqi in the upper reaches of the Yangtze River,the distribution types of the vertical flow velocity of the river are summarized.We studied the vertical flow velocity distribution of “3”type by fractal theory.The influence of flow rate,water level and channel slope drop on the fractal dimension are discussed.The results show that:the vertical flow velocity distribution of the river segment can be divided into:“3”type,“anti-3”type,“C”type,“anti-C”type,“1”type,“S”type,“7”type,“anti-S”type and“class index”type,and the “3” type of the vertical flow velocity distribution has the highest frequency.There is a fractal phenomenon in the “3” type of the vertical flow velocity distribution and it has a first-order accumulated variable-dimensional and fractal phenomenon.It is essentially a result of the deviation of logarithmic flow velocity distribution under the action of a variety of factors.The fractal dimension of vertical flow velocity distribution is positively correlated with flow,water level and slope,but the three factors have little effect on fractal dimension.