Objective;To study the pharmacokinetics of Nerve G rowth Factor(NGF)一liposome in rabbit by isotopic tracing.Methods①NGF was labeled with 'TC ,and its -i-ray counts were detected by isotopic tracing and trichloroacetic acid (TCA) precipitation method. From cpm of -1-ray and NGF content of samples, the standard curve was drawn and it was nearly a line.②9"'TC-NGF was packed with liposome and injected into rabbits (n=5) body from vena auris.③Blood samples of rabbit were collecteda td ifferentti mes (0.5，1,3,5，10,15 ,30,60,90,120,150,180,210,240m in)a fterin jection.T het echniques abovew ere used to detect NGF concentration in rabbit blood and data were input into computer to analyze the pharmacokinetic parameter by software(3P87). Results: The metabolism of NGF-Liposome in vivo in rabbits was fitted to the double-compartments model. With the dose of 40mg/kg,the p harmacokinetics parameters were as the follows:t-α=0.2338 h ,t-β=1.3229h ,A U C= 106.57ng/h.ml-1 Conclusion: NGF-liposome has some slowly-release function compared to NGF.