The energy input needed by human community in the watershed was mainly from grain, fuel and food oil, meanwhile the human community provides the watershed including sub systems of farming, forestry, animal husbandry and itself with human labour power and the organic energy of excrement, etc., the ratio of output to input of energy is 0.151∶1. Through systematic analysis of energy flow, it is found that the use rate of solar energy of the crops could be ordered as hemp