Abstract: Objective To estimate the exposure of phytoestrogens among the children in Tianjin city and to compare the exposure level to those of Chinese adults and children in US.Methods The morning urine samples from 50 children aged 9-10 years in 3 primary schools in central urban areas of Tianjin were collected in April to May,2013 and detected with ultra-performance liquid chromatography tandem mass spectrometry(UPLC-MS/MS)for the determination of 6 typical phytoestrogens.Results The five phytoestrogens in the urine samples with higher detection rate were daidzein,genistein,O-desmethylangolensin,enterolactone,and enterodiol,with the concentrations of daidzein of 260 ng/mL for the samples from the boys and 218 ng/mL from the girls and those of enterolactone of 127 ng/mL for the samples from the boys and 164 ng/mL from the girls.Conclusion Daidzein and enterolactone are dominant phytoestrogens in urine among the children in Tianjin city.