Abstract: The stationary phase of silica gel bonded with poly N-isopropylacrylamide (SI-PNIPAM) ,was prepared from N-isopropylacrylamide,and applied to the separation of alkaline substances from esters.It was found that the separation of baseline from the components was achieved satisfactorily with symmetrical chromatographic peaks.The thermo-sensitive of SI-PNIPAM,by which phase transition from hydrophilic conformation to hydrophobic conformation was taken place in the temperature interval of 28-32 ℃ with a mixed solution of methanol-water (30+70) as mobile phase,was feasible to be applied to the analysis of polar compounds with obvious differences in polarity.