Objective:To study the composing rule of the similar formulae of Zhizidahuangtang and provid guidance for composing formula of treating jaundice of heat and dampness type.Method:Searching the formulae of previous treating pestilence for the formula of Zhizidahuangtang and its similar formulae

20 formulae talally found were analyzed for each composition herb’s frequency

nature and taste by statistic method for Chinese medicine.Result:（1）There are 42 kind of different herbal drugs used in the similar formulae of Zhizidahuangtang

and among them

Dahuang

Zhizi

Yinchen were most frequently used.（2）Among the compositions of the similar formulae of Zhizidahuangtang

the herbs with cold and cool nature got score of 2.631;the herbs with heat and warm nature got score of 0.257;the rate of cold herbs to heat herbs was about 10∶1.（3） Among the compositions of the similar formulae of Zhizidahuangtang

the herbs with bitter taste was used mostly

herbs with spicy taste were secondly used and sweet ones thirdly.The amount of the three kinds of herbs took 87.2% of all the herbs and 92.2% of all score for the tasle of herbas.The herbs with sour

salty or tasteless taste were far less used.Conclusion:（1） Dahuang

Zhizi

Yinchen are the most common and basic herbs used in treating jaundice of heat and dampness.The formula Yinchenghaotang is the fundamental of treating jaundice of heat and dampness.（2） The formulae of Zhizidahuangtang are mainly composed with cold nature and bitter taste

assisted with a few warm and spicy ones.The together using of using cold and warm

bitter and spicy herbs was not only characterige for formulation of Zhizidahuangtang

but also a formulae rule in treating jaundice of heat and dampness.