Objective:To research the penetration to blood brain barrier(BBB) after nerve growth factor(NGF) packed with liposome. Methods:The 4.0mCi of 99mTc-NGF packed with liposomeA,4.0mCi of 99mTc-NGF packed with liposomeB and free 99mTc-NGF were injected into the rabbit by the vein of ear border respectively. SPECT was used to detect the distribution of 99mTc-NGF. And then the ratio of radioactivity counts were calculated to describe the character of distribution in brain;The NGF concentration in CSF was detected by ELISA after the NGF was injected into the rabbit at 30,60,90,120 min. Results:The results of imaging with SPECT showed that 99mTc-NGF packed with liposomeA was aggregated in brain; while 99mTc-NGF was evacuated through urinary system. In addition,99mTc-NGF packed with liposomeB was aggregated in liver;The NGF concentration in CSF showed that the NGF packed with liposome could penetrate the BBB partly. Conclusion:The ratio of brain tissue signal intensity to body signal intensity of NGF packed with liposomeA obviously exceeded that of NGF and liposomeB from beginning to terminal. The NGF packed with liposomeA could help the NGF penetration the BBB.