Taking the case of Niqiu river and Keluo river, the relation of land use/cover change with river runoff is discussed. When total precipitation increases in Niqiu river watershed, surface runoff decreases. The change of forest cover results in decreasing of evaporative capacity. However, superfluous water has not formed surface runoff but was stored in mire wetland transformed from forest and grass land. The surface runoff was increased in Keluo river watershed because the forest area decreased. Forest change affects surface runoff more than farmland change. The relation of land use /cover change affecting river runoff is complicated, and it is not the result of unique land use/cover change, but the coupling operation of land use/cover change which affects river runoff. In general, the change of marsh is most effective in all the change.