The Ponciri fructus immaturus (Poncirus trifoliata Rafinesque) has been used in oriental medicine for uterinecontraction, stomachache, abdominal distension and cardiovascular diseases. Two main compounds, poncirin and naringinwere successfully analyzed by high performance liquid chromatography (HPLC) and carried out method validation accordingto ICH guideline. A successful resolution and retention times were obtained with a C18 reversed phase column, at an 1㎖min−¹ flow rate, with a gradient elution of a mixture of methanol, water and acetonitrile. Poncirin and naringin showed goodlinearity (R²>0.999) in relatively wide concentration ranged. The recovery of each compound was 95.81~101.48% withR.S.D. values less than 1.0%. The application of ultrasound-assisted extraction was shown to be more efficient in extractingponcirin and naringin from Ponciri fructus immaturus. The predicted optimal poncirin and naringin yield were poncirin2.15%, naringin 1.65% under an extraction temperature of 40℃, an extraction time of 10 min in a solvent of 70% methanol.