Objective: This study aimed to help with improving and increasing the added value of highland barley. Methods: Back highland barley powder was used as raw material to prepare low content rapidly digestible starch by α-amylase. Highland barley powder with low content of fast digestible starch was prepared by α-amylase. The optimal technological conditions for reducing the content of fast digestible starch in highland barley were optimized by response surface test with the content of fast digestible starch as the index, and the hypoglycemic activity in vitro was evaluated by the inhibition rate of α-glucosidase and α-amylase. Results: The optimum conditions for α-amylase preparation of highland barley powder with low content of fast digestible starch were as follows: α-amylase dosage of 150 U/g, solid-liquid ratio of 1∶10 (g/mL), enzymolysis at 65 ℃ for 2 h. Under the control of these conditions, the content of fast digestible starch in black highland barley was 11.6%, and the content of slow digestible starch was 13.0%, with 75.4% of the resistant. After enzymatic hydrolysis, the highest inhibition rates of α-glucosidase and α-amylase were 75.86% and 75.54%, respectively. Conclusion: The method can greatly reduce the content of fast digestible starch in highland barley.