This paper introduces analysis of RP HPLC for amino acids,which uses OPA/MCE and FMOC derivatives with two fluorescence detectors.The system's error is removed through Internal Standard,i.e.HCYS,HSER,NVAL,TPRO.Meanwhile,the method' accuracy is determined by relative error of recoverity with all kinds of amino acid's ramification.The result shows:it is an ideal method for amino acids'analysis with better sensitivity,detection limits and recoverity,overcoming the limitation by single ramification & only one detector.In addition,it gets over influent of the peak of NH 3 to column.And the relative error of retentive time is <5% & experiment of recycling is >90%,which explains credibility of the method.