Mountain resource-based cities, for its complicated geography condition, intense human activities and serious pollution, are vulnerable to the imbalance of water resources allocation and utilization under the climate change, which causes severe water security problems. Dongchuan district is a typical resource-based city in the Southwest Mountainous Region in China,which was double threatened by water quantity decrease and quality deterioration under the regional drought in recent years. In this study, the water in 13 rivers include main streams and tributaries in Dongchuan was sampled; and 63 questionnaires were investigated for the drinking water and irrigation difficulties of the Natural villages in different altitude,in order to analyze the existing water security problems and propose Strategies and solutions. The results showed that, most of the rivers in Dongchuan are polluted by heavy metals in several degrees, which means rivers are hard to utilize; those villages which use springs for their drinking water and rain for the irrigation in middle or high mountain area (altitude more than 1 600 m) would have higher risks of water shortages in drought period, and the natural village in the valley would strongly infected by the river pollution for their farmland irrigation largely depend on rivers. To solve the problems above, firstly, heavy metal emissions should be control strictly and the water quality in rivers should be recovered; secondly,the damaged vegetation,especially the forest, in the middle and high mountain area should be restored, which could provide stable water supply for the region; thirdly,the construction of small water conservancy facilities could be great improvement for the utilization efficiency of water resources. The status of water security in Dongchuan has universality in Mountain resource-based cities. The strategies provided in this study could give effective references for the prevention and control of water security problems in these areas.