Thermosensitive polymer hydrogels were prepared by the copolymerization of three kinds of acryloyloxyethyl trialkyl phosphonium chlorides (AETRs) with alkyl chains of different lengths, with N-isopropyl acrylamide (NIPAAm) and N,N'-methylenebisacrylamide (MBAAm). The water content of the AETR-NIPAAm-MBAAm terpolymers obtained at molar ratios of the crosslinking agent greater than 2 decreased with increasing temperature and decreased sharply around 35 degreesC. However, the water contents of the AETR-NIPAAm-MBAAm (X/100/1) terpolymers obtained at a molar ratio of 1 of the crosslinking agent increased once with increasing temperature and then decreased from 3 to around 40 degreesC. The water contents of the AETR-NIPAAm-MBAAm (3/100/1 or 2) terpolymers decreased with the increasing length of alkyl chains in phosphonium groups in the terpolymers. The water contents of the AETR-NIPAAm-MBAAm terpolymers increased by the addition of a small amount of urea and then decreased with increasing urea concentration. However, the water contents decreased abruptly with the addition of NaCl. The AETR-NIPAAm-MBAAm terpolymers exhibited high adsorption for sodium dodecylbenzene sulfonate but no adsorption for sodium benzene sulfonate.