With Dioscorea opposita‘Tiegun’as the research materials,phenylalnine ammonialyase( PAL) characteristics related to browning and the effects of different inhibitors on PAL activity were studied by spectrophotometry. Research results showed that within the test range,the optimal p H was 8. 6 for PAL of D. opposita‘Tiegun’. PAL had poor tolerance to acid and alkali. The optimal temperature was 50 ℃,showing certain tolerance to high temperature. Even under incubation for 30 min at 80 ℃,there were still about 12% PAL activity. L-cysteine hydrochloride and citric acid had significant inhibitory effects on PAL; while phytic acid had no significant inhibitory effects on PAL activity; but phytic acid showed no significant inhibitory effects. Sodium chloride promoted the PAL activity. In order to effectively restrict the browning of fresh slices of D. opposita‘Tiegun’caused by PAL,processing and storage of D. opposita‘Tiegun’slices should be carried out under acidic condition( p H < 2. 0),low temperature( < 20 ℃) or high temperature( > 80 ℃). L-cysteine hydrochloride should be the first choice of antibrowning reagent without sulfite for fresh slices,followed with citric acid. With Dioscorea opposita’Tiegun’as the research materials, phenylalnine ammonialyase (PAL) characteristics related to browning and the effects of different inhibitors on PAL activity were studied by spectrophotometry. Research results showed that within the test range, the optimal pH was 8. 6 for PAL of D. opposita’Tiegun ’. PAL had poor tolerance to acid and alkali. The optimal temperature was 50 ° C, showing some tolerance to high temperature. Even under incubation for 30 min at 80 ° C, there were still about 12% PAL activity. L-cysteine ​​hydrochloride and citric acid had significant inhibitory effects on PAL; while phytic acid had no significant inhibitory effects on PAL activity; but phytic acid showed no significant inhibitory effects. Sodium chloride promoted the PAL activity. the browning of fresh slices of D. opposita’Tiegun’caused by PAL, processing and storage of D. opposita’Tiegun’slices should be carried out under acidic conditions (p H < L-cysteine ​​hydrochloride should be the first choice of antibrowning reagent without sulfite for fresh slices, followed by citric acid. 2. 0), low temperature (<20 ° C) or high temperature