Taking precipitation, temperature, relative humidity and sunshine duration in Yangtze River Basin during the year of 1961-2010 as the basic climatic elements, the relationship between the runoff and the climatic elements and the response of runoff to climate change were analyzed. The results indicate that the runoff is very sensitive to the climate change in the middle and lower reaches of Yangtze River Basin, where the precipitation is the key factor affecting runoff changes and its effect magnitude on the runoff is approximately 2 times, 4 times and 39 times as much as that values of relative humidity, air temperature and sunshine duration. The results also reveal that the response of runoff to the single climatic element variation is less than to the multi-elements coupling changes, when these elements increase or decrease in the same direction. However, when some elements increase while others decrease, the response of runoff to the single climatic element is higher than the multi-elements coupling changes. This respond is significant with the more elements coupling changes together.