OBJECTIVE：To study the pharmacokinetics and tissue distribution characteristics of Hydroxycamptothecin （HCPT） nanoparticles in rats ，and to investigate their targeting. METHODS ：Male SD rats were randomly divided into 2 groups，with 6 rats in each group. They were given HCPT nanoparticles and HCPT injection （4 mg/kg based on HCPT ）via tail vein respectively. 500 μL fundus venous plexus blood were sampled at 5，30，60，120，240，360，480，600 and 720 min after administration. The plasma concentration of HCPT in rats were measured by HPLC at different time points. The pharmacokinetic parameters were calculated by DAS 3.0 software. Male SD rats were randomly divided into two groups ，with 24 rats in each group. They were given HCPT nanoparticles and HCPT injection （0.6 mg/kg based on HCPT ）via tail vein ，respectively. Blood was immediately taken from the abdominal aorta ，and heart ，liver，spleen，lung，kidney and brain were removed at 30，60，120，240 min after administration. The plasma and tissue concentration of HCPT in rats were measured by HPLC. The distribution of HCPT ineach tissue and targeting were investigated. RESULTS ：HCPT nanoparticles and its injection conformed to a two-compartment model in rats. Compared with HCPT injection ，AUC0-720 min andAUC0- ∞ increased by 1.89 and 1.87 times respectively ， MRT0-720 min and MRT 0- ∞ increased by 2.74 and 3.00 times respectively， t1/2 β increased by 2.75 times，with statistical significance（P＜0.05）. At 30 min after administration ，HCPT nanoparticles and HCPT injection had the highest concentration in lung；with the passage of time ，the drug gradually accumulated in the liver and reached the highest concentration at 60 min. The relative liver uptake rate of HCPT nanoparticles was the highest （6.28）. Taking liver ad target organ ，and the targeting efficiencies of it in heart ，spleen，lung，kindey，brain and plasma were higher than those of HCPT injection. The selectivity index of HCPT nanoparticles in heart ，lung（except for 30 min after administration ），kidney，brain and plasma were significantly higher than those of HCPT injection at 30-120 min after administration. CONCLUSIONS ：HCPT nanoparticles extend the half-life of the drug ， increase its plasma concentration ，and prolong its action time in vivo ，with significant liver targeting.