Objective: To research the extracting technology for Tuibai decoction. Method: Orthogonal design method is used to assay psoralen and isopsoralen in Tuibai decoction prepared with different extracting methods. The best extracting method is designed according to the result of these studies. Result: Quantity of water and decoction time had significant influence to the results of extraction. The best extracting method was 10 times of quantity of water

soaked for 1 h

and decocted for 2 times

and 1h for each time. Conclusion: The optimized extracting method is cheap and effective

and easy to operate.