Abstract: The recombinant retinoid X receptor (RXR) gene yeast was conducted to assess the RXR ant/agonistic activities of effluents collected from wastewater treatment plant (WWTP) at a city in south China. Also, a metabolic activation method was introduced based on rat liver S9 for screening indirect RXR ant/agonists activity. The results indicated all of the samples including influent and effluent couldnt induce the enzyme activity. But, compared with blank control, all samples with higher concentration obviously inhibited the enzyme activity induced by 9-<em<cis</em<-retinoic acid. After metablization, the agonistic activation were found in all samples, and the antagonistic activation were also found in some samples, suggesting that there are a lot of chemical compound with RXR ant/agonists in wastewater. All of the results demonstrate that the present treatment processes could remove some RXR ant/agonists and suggest that the combined method of recombinant RXR gene yeast assay with S9 metabolic activation can be used for screening the RXR ant/agonistic activity of environmental samples.