Based on 26 single-peak floods between 1965 and 2009 in the Dapoling sub-watershed (or Dapoling Basin) in the upper Huaihe River, the mean basin lag time was calculated. The observed data were delimited by the year 1985 according to the land use change to compare the variation of mean basin lag time, calculate the lag time for different rainfall depths, and analyze the respective relationship of lag time with runoff depth and peak discharge. The results show that the land use change caused a large variation of the mean basin lag time. The lag time from the centroid of the rainfall hydrograph to peak time TLPC decreased from 9.98h to 5.26h after the land use change. The lag time from the centroid of the rainfall hydrograph to the centroid of the discharge hydrograph TLC, the lag time from the beginning of a rainfall event to peak time TLP,and the lag time from the peak rainfall intensity to peak discharge TLPP increased after the land use change. The TLC, TLP, and TLPP values increased from 21.32h to 26.77 h, from 34.64 h to 35.08 h, and from 10.00 h to 11.50 h, respectively. During the periods before and after land use change and the entire period in the Dapoling Basin, there was a certain relationship between the four lag time variables and the rainfall depth, but no relationship was found between lag time and runoff depth or between lag time and peak discharge.