OBJECTIVE： To develop a method for determining entrapped efficiency of Irinotecan hydrochloride liposomes. METHODS： The improved hollow fiber centrifugal ultrafiltration （HFCF-UF） method was employed to separate the liposomal drug and the free drug. The content of irinotecan hydrochloride was determined by HPLC. The determination was performed on Diamonsil C18 with mobile phase consisted of methanol-acetonitrile-phosphate buffer solution （monobasic potassium phosphate 6.8 g dissolved in 800 mL water， triethylamine 10 mL， pH adjusted to 4.0 with phosphoric acid， adding water to 1 000 mL） （55 ∶ 5 ∶ 45，V/V/V） at the flow rate of 1.0 mL/min. The detection wavelength was set at 254 nm， and column temperature was 25 ℃. The sample size was 20 μL. RESULTS： The linear range of irinotecan hydrochloride were 2.55-40.80 μg/mL （r＝0.999 2）. The limit of quantitation was 0.64 μg/mL. RSDs of intermediate precision， stability and reproducibility tests were all lower than 2％. The recovery rates of ultrafiltration were 96.9％-100.2％ （RSD＝1.0％，n＝9）， and the blank adding recovery rates ranged 95.5％-100.5％（RSD＝1.7％，n＝9）.  The average of entrapped efficiency was 94.85％（RSD＝1.1％，n＝3）. CONCLUSIONS： The method is simple， accurate， precise， stable， reproducible and durable. It can be used for the determination of entrapped efficiency of Iriticonite hydrochloride liposomes.