Various aminosulfonic acidbased superplasticizers(ASP) were synthesized with different mole ratios of phenol to sodium sulfanilate(n(P)/n(SS)). The effects of adsorption characteristics on dispersion and fluidity retention for cement suspensions were investigated to elucidate the action mechanism. It is found that the adsorption rate of ASP on cement grains increases with the increasing n(P)/n(SS) while dispersibility and slump retentionability improve evidently at first and decline greatly afterward. A linear positive correlation between dispersion and adsorption amount is observed at the same n(P)/n(SS), whereas no similar conclusion is drawn between fluidity retention and the concentration of ASP in the pore solution probability due to other mechanisms.