Objective:To study the difference on contents of key components in formula granule,single and mixed decoction of Huanglian(Coptidis Rhizome)and Wuzhuyu(Evodiae Fructus)with equal proportion,and explore the equivalence of formula granule and traditional decocting method in couplet medicines. MethodsThe contents of 6 kinds alkaloids in formula granule,single and mixed decoction were determined by HPLC,including berberine,coptisine,palmatine,epiberberine,rutacarpine and evodiamine,and the statistics analysis was performed by SPSS18.0.  Results:There was obvious differences on the contents of coptis alkaloids. The contents of berberine were(0.64±0.07)% in the mixed decoction and(1.29±0.17)% in the single decoction；compared with the mixed decoction,the content of berberine was significantly increased in the single decoction(P<0.001). The contents of coptisine were(0.45±0.05)% in the mixed decoction and(0.33±0.04)% in the single decoction；compared with the mixed decoction,the content of coptisine was significantly decreased in the single decoction(P=0.020). The contents of palmatine were(0.48±0.03)% in the mixed decoction and(0.36±0.03)% in the single decoction；compared with the mixed decoction,the content of palmatine was significantly decreased in the single decoction(P=0.002). The contents of epiberberine were(0.30±0.03)% in the mixed decoction and(0.23±0.03)% in the single decoction；compared with the mixed decoction,the content of epiberberine was significantly decreased in the single decoction(P=0.017). The content of palmatine was(0.42±0.03)% in the formula granule,which was slightly decreased compared with the mixed decoction(P=0.038). There were no obvious differences on the contents of berberine,coptisine and epiberberine between the formula granule and mixed decoction(P>0.05).There were no statistically significant differences on the contents of rutacarpine and evodiamine among formula granule,single and mixed decoction(P>0.05).  Conclusion:There was no significant difference between the formula granule and mixed decoction of Huanglian(Coptidis Rhizome)and Wuzhuyu(Evodiae Fructus). But there were obvious differences on the contents of coptis alkaloids between the single and mixed decoction.