Abstract:  This paper studied the acid hydrolysis conditions of fenugreek neutral polysaccharide. The orthogonal test table L9 (34) was used to optimize 3 factors, namely HCl concentration, reaction time and reaction temperature. The yield of oligosaccharide was used the index in the orthogonal test. Results showed that as far as the yield of oligosaccharide was concerned, it would be as high as 43.97% when under the conditions of 6mol/L HCl, 100℃ reaction temperature and 1h reaction time, where as the molecular weight of the obtained oligosaccharide is about 500～900Da. For the final goal to obtain small molecule oligosaccharide, the optimal conditions would be 6mol/L HCl, 90℃ reaction temperature and 2h reaction time. Under the conditions, the molecular weight of the obtained oligosaccharide is about 500～1000Da and its yield is 43.97%.

Key words:  , fenugreek neutral polysaccharide； acid hydrolysis； orthogonal test； the yield of oligosaccharide； the molecular weight of oligosaccharide；