Nonylphenol　(NP)　having　endocrine　disrupter　activity　is　an　ultra　trace　component　in　sewage　and　reuse　wastewater.　There　are　many　NP　isomers　in　the　wastewater　because　nonyl　structure　is　different.　The　background　impurity　of　the　samples　is　very　complex　with　many　other　components.　So　it　is　difficulty　for　quantitative　analysis　of　NP　in　the　samples.　About　seventy　sewages　and　recycled　wastewater　samples　were　measured　for　the　content　of　NP　isomer　mixtures　by　solid-phase　extraction-gas　chromatography-mass　spectrometry　and　multi-selected　ions　monitoring　(shortened　as　SPE-GC-MS-SIM).　The　results　show　that　hydrophilic-lipophilic-equilibrium　solid-phase　extraction　pole　has　selective　adsorption　for　NP,　so　that　the　samples　can　be　concentrated　from　50　to　200　times.　The　five　kinds　of　mass　spectrum　ions,　i.e.　107,　121,　135,　149,　163,　have　higher　abundance　and　distinct　character.　The　sum　of　five　selected　ion　monitoring　(　summation　SIM)　is　from　54.4　to　73　percent　of　the　total　ion　current　for　NP,　which　can　accurately　represent　different　NP　isomers.　Quantitative　analysis　base　on　the　spectral　integral　of　the　2　SIM　chromatograph　can　eliminate　interference　with　background　signal　and　ensure　selectivity,　accuracy　and　precision　of　the　method.