Objective: To study on influence of different compatibility of Chaihu Shugan powder on dissolution of saikosaponin a.Method: L8（27） orthogonal design method was used with determining the content of saikosaponin a in each compatibility samples by HPLC/DAD

and data was analyzed by single-factor variance analysis.Result: Influence degree of every factors in orthogonal test on dissolution of saikosaponin a was:guide> adjuvant> associate.Effect of it（dissolution of saikosaponin a） had significant difference by single-factor

but there was no significant difference in interaction.It had significant difference among groups in the 4 groups classified.In the different number of drugs classified

dissolution of saikosaponin a was different in every major groups with different compatibility

dissolution rates among every groups:the compound group> five-five compatibility group> single-decoction group> six-six compatibility group

two-two compatibility group> four-four compatibility group> three-three compatibility group.Conclusion: Dissolution of saikosaponin a was lower from groups including Radix Paeoniae Alba

Rhizoma Cyperi and Rhizoma Chuanxiong

it was higher from groups including Auranti Fructus and Glycyrrhiza Uralensis

it was the highest from the compound group.