Objective To establish the determination method of Codeine phosphate in Qiangli Pipa Syrup by RP-HPLC.Methods Using XDB-C18 Eclipse column (250 mm × 4.6 mm,5 ìm),acetonitrile:0.035 mol/L sodium acetate solution (glacial acetic acid to adjust pH =3.5) (25:75) as mobile phase,the flow rate was 1.0 mL/min,the detection wavelength is 240 nm,the column temperature is 40.Results the linear range of codeine phosphate in 2.024-40.24 ìg/mL was goody =8.18 × 105x + 12.2 (r =0.999 2);the average recovery rate was 98.2％ and RSD was 1.0％ (n =6).Conclusion This method is simple,rapid,accurate,and reliable,with high sensitivity,and could be applied to determination of Qiangli Pipa Syrup codeine hydrochloride content and controlment of the drug quality.