Objective:To study the factors which affect the preparation of dropping pills of Flos Sophorae Im-maturus and acquire the optimum preparation process.Method:The main evaluation criteria include the apparent quality

melting time and difference between pill weights by using orthogonal design.The substrate was a mixture of po-lyethylene glycol 6 000 and polyethylene glycol 4 000（with a ratio of 9:1）;the mass ratio of rutin to substrate was 1 :3 at the temperature of 82 ℃;condensate was dimethicone at 7 ℃.The dropping speed is 50 drops per minute and the inside diameter of the dropping tip was 4.5 mm.Result:The content of rutin in pill was determined with absorben-cy at 410 nm by using the ultraviolet spectrophotometry-AlCl3 method;and the linear range was from 10 to 60 mg·L-1（r =0.999 7）.Conclusion:Under the above preparation process

the type of dropping pills had stable rutin

a fine ap-pearance

a short melting time and subtle difference between pill weights;in the mean time the above preparation process is accurate

convenient and can be used as quality control method for Flos Sohporae Immaturus.