Abstract: The principles of foam separation, diffusing separation and their coupling purification have been successfully applied to the coupling purification technology of tara tannin extract solution in industrial scale, which satisfied the requirements of production of tara tannin acid. It was showed that the concentration of tara tannin extract solution should be 2-5°Be' at 35-60℃, the flowing height of solution was 1.0-1.5m. Fine fiber amount separated from foam floatation fine was 12.73% of total solid in obtained tara tannin extract solution. The foam of tara extvact solution was mainly characterized by its hexagonal structure, foam layers were 3-5, foams life was 3-1200s, foam diameter was about 2-12mm.