In order to determine the variety and contents of the neutral sugar in sugar beet pectin ( SBP) ,a twostep hydrolysis method was proposed for the SBP.In the method,the neutral sugar in the SBP were sequentially hydrolyzed by using pectinase and trifluoroacetic acid ( TFA) .First,the SBP was degraded into the fractions of smaller relative molecular mass by pectinase.Second,the neutral sugar attached to the SBP were liberated into solution by TFA.Among three commercial pectinases,Rapidase C80 was selected as the objective pectinase because of its lower endogenous monosaccharide content and better hydrolyzing activity.It is found that the optimal hydrolysis parameters of C80 are 50℃,pH 5 and 15 h.Moreover,the effects of the TFA concentration,the temperature and the hydrolysis duration on the hydrolysis of the neutral sugar were further investigated.By compromising the hydrolysis rate and the degradation rate of the neutral sugar,suitable TFA concentration,temperature and hydrolysis duration were respectively determined to be 1mol /L,110℃ and 4 h.The HPAEC analysis results show that the proposed method has a good effect in achieving rhamnose through hydrolysis,and it exhibits a good stability and a high repeatability,which means that this method can be used to quantitatively analyze the neutral sugar in the SBP.