Ecological effect evaluation of water diversion is a difficult and long-term process requiring complex monitoring data and scientific evaluation method. Based on remote sensing data and the ecological investigation data of Yellow River delta, this study built a wetland ecology evaluation index system with the analytic hierarchy process (AHP) framework, which included 13 evaluation indices of three criteria as suitability, diversity, and functionality. Fuzzy-AHP comprehensive evaluation method was used to evaluate the ecological effect of water diversion at Diaokou River wetland restoration zone. The results show that the comprehensive evaluation index (CEI) of wetland ecology is 0.464 before water diversion, which belongs to the ‘poor’ level, while after five years of water diversion, the CEI increased to 0.737, which belongs to the ‘fine’ level. It represents that ecological water diversion has made prominent positive effects for the ecosystem of Diaokou River wetland restoration zone. The research result could give decision-makers a clear understanding about the ecological effect of wetland water diversion and provide scientific guidance for strategic decisions.