In view of the problems of the frame type-oblique paddle agitator used in acylation reaction tank in Hebei Jiheng ( Group )  Pharmaceutical ( Corporation Ltd. ), such as more  clumsy design, difficulty to fast fusion between liquid, slower reaction, lower yield and higher energy consumption, the original stirrer was transformed into double-layer-three-narrow-blade propeller. The new stirrer overcomes the shortcomings of the original stirrer, the reaction time is shortened to about 10 h from about 12 h, the mass transfer process between solid and liquid is strengthened, the yield is increased.