Many military garrisons had been built in Yunnan province during the period of Ming Dynasty,which had brought a large number of immigrants in and thus directly prompted the economic and social development of Yunnan province. Meanwhile,it also produced some new disputes and problems,among which were water conservancy disputes. After the establishment of military garrisons in Yunnan,water conservancy disputes there increased and became much more complicated day by day. The typical cases of water conservancy disputes present all saw the presence of military garrisons. The increase of population and arable land brought by the establishment of military garrisons had strained the local resources over a period of time,which was the immediate cause of the water conservancy disputes. However,the root of these disputes were not in the military garrison system,but in the backward development of water conservancy construction.