To study the transport and behaviour of short chain nonylphenol ethoxylates (NP_nEO, n=1,2) in anoxic／oxic (A／O) process of municipal wastewater treatment plant, the distribution of short chain NP_nEO and NP in the aqueous phase and sludge of each unit process in a full-scale municipal wastewater treatment plant of northeast China were investigated using a solid phase extraction-gas chromatography-mass spectrometry (SPE-GC-MS). The results showed that the influent NP, NP₁EO and NP₂EO were 1 3,1 784 and 891 ng／L, which were lower than those of other cities in China and many other countries, then the concentrations of three compounds increased and reached to the highest at aeration grit chamber due to the biodegradation of long chain NP_nEO, which were 3 6,4 228 and 2 066 ng／L, respectively, after that the concentrations of them were dropping down significantly at anaerobic sink because of the adsorption of activated sludge, and finally the effluent NP, NP₁EO and NP₂EO were 1,8 and 159 ng／L. It is concluded that the anaerobic sink made more contribution for the removal of these compounds in influent. In addition, the concentrations of NP, NP₁EO and NP₂EO in each treatment unit have a positive correlation with their TOC content.