Abstract: In order to analyze the environmental risk of reclaimed wastewater,based on the monitored results of nonylphenol in several urban lakes from various supply water models in Beijing,and with a review of the phenol toxic parameter from integrated risk information system of the Unite State Environmental Protection Agency and the nonylphenol toxic tested data on fish from interrelated organizations and documents,the primary fish sex transformation risk assessment of nonylphenol was conducted by using the criterion of risk quotient when the sewage was reclaimed as the landscape complementary water.The results indicate that the risk quotient can not be ignored,and some measurements should be taken to reduce the risk.When the proportion of supplying reclaimed wastewater for urban lakes is smaller than 50%,the standard of nonylphenol in reclamation wastewater was proposed as 2μg/L.