Reclaimed water as an unconventional water resource plays an increasingly important role under the present situation of water resources shortage and water pollution. Aiming at the problem of single index system of the current reclaimed water evaluation and the irrationality of the weight calculation, a reclaimed water comprehensive development capacity model was established in this paper which contained 16 indexes and the improved gray situation decision method and combination weighting method were used to calculate the model. The exponential whitenization function was introduced to avoid the loss of useful information and solve the problem of zero weight. And the weight of each index was calculated by the combination weighting method which combined with AHP method and entropy method. Based on the improved grey situation decision method and combination weighting method, the evaluation model of comprehensive development capability of reclaimed water is established. The validity of the model was verified by an example of three cities in Yunnan Province. The results showed that the assessment of the comprehensive development capacity of reclaimed water in the three cities is K> Y > L, which are consistent with the actual results, indicating that the model is suitable for evaluating the comprehensive development ability of reclaimed water.