[Objective] Water resource security was evaluated to provide scientific basis for water environment management and sustainable development in Karst area.[Methods] A case study of Guizhou Province in karst was carried out and an evaluation index system of water resources security was established. The BP artificial neural network model was constructed to evaluate the water resources securities of 9 cities in Guizhou Province, and the results were compared with entropy weight matter element model.[Results] Water resource securities of 9 cities were evaluated in Guizhou Province, among which two cities were assessed at relatively safe level, six cities at general level, and one city at relatively unsafe level. The evaluation results were basically the same to the results of the entropy weighted matter element model. [Conclusion] The results are reasonable and the method is simple and intuitive. The model has certain reference value for similar areas of water resources security evaluation.