To assess the ecological risk of stock enhancement, an ecological risk assessment (ERA) system was constructed based on the analysis of the past literatures, field survey and expert consultancy. The system constructed using analytic hierarchy process (AHP) method was applied to 5 zoobenthos. The results showed that: the risk grade of Coelomactra Antiquata, Anthocidaris crassispina, Meretrix lamarckii, Babylonia lutosa was medium, and that of Paphia undulate was low. The construction of this risk assessment system will provide beneficial suggestions in the future stock enhancement.