Objective: To optimize ultrasonic-assisted alkali extraction and acid precipitation technology of total flavonoids from Acalypha australis. Method: UV spectrophotometry was used to determine the content of total flavonoids with rutin as a control component.With yield of total flavonoids as index

based on single factor test

effects of solid-liquid ratio

pH of alkaline extraction solvent

temperature

acid precipitation pH and time on extraction technology were investigated by orthogonal test. Result: The best extraction technology was as following:solid-liquid ratio of 1: 20

pH of extraction solvent 11

extracting temperature of 60 ℃

acid precipitation pH of 2.5

and ultrasonic time of 90 min.Under these conditions

extraction amount of total flavonoids from A. australis was 24.11 mg·g-1

and its yield could reach 87.76%. Conclusion: This optimized technology was stable and feasible with high extraction rate

it could provide experimental basis for development and utilization of A. australis.