Objective:To optimize preparation technology of hydroxycamptothecin（HCPT） magnetic liposomes and examine its in vivo targeting aggregation.Method: With Fe3O4 magnetic nanoparticles as material whose surface was modified by oleic acid

soybean lecithin and cholesterol as raw material

HCPT magnetic liposomes was prepared by film dispersion-ultrasound method with encapsulation efficiency as index

preparation technology of HCPT magnetic liposomes was optimized by orthogonal test.Local tumor aggregation of magnetic liposomes was dynamic and continuous investigated by microdialysis technique.Result: Optimized prearation conditions of HCPT magnetic liposomes were as follows:ratio of drug-lipid 25∶1

phospholipid-cholesterol 80∶30

preparation temperature 45 ℃

hydration medium phosphate buffer solution（pH 6.8）.The highest encapsulation efficiency of 66.8%

drug loading of 2.57%.In tumor-bearing mice in vivo magnetic targeting positioning test

the drug concentration at site of tumor of HCPT magnetic liposomes additional magnetic field group was higher than group without magnetic field and injection group

it proved that HCPT magnetic liposomes had obvious magnetic targeting effect under guidance of additional magnetic field.Conclusion: HCPT magnetic liposomes showed particle size uniformity

stable dispersion

high encapsulation efficiency and good magnetic targeting

which prepared by oleic acid-modified Fe3O4 and film dispersion-ultrasonic method.