Objective To observe the distribution and concentration of 125I-nerve growth factor (NGF) in rabbitsprime; eyes after intravitreal injection and posterior juxtascleral injection.Methods Intravitreal injection(group A) and posterior juxtascleral injection (group B) were performed with the dosage of 30mu;g/100mu;l 125I-NGF on left and right eyes in 45 white rabbits respectively. The gamma;-counts and the concentration of 125I-NGF (％ID/g) of each ocular tissue was determined 15 and 30 minutes, and 1,3,6,12,24,and 48 hours after injection. Results The 125I-NGF diffusion in group A was faster in ocular content and ocular inner wall. The vitreous content of 125I-NGF decreased gradually in group A, the curve changes in other eye tissues were normal. The concentration of 125I-NGF reached the peak 3 hours after injection in aqueous humor, iris and ciliary body, retina, and choroids, but 6 hours after injection in sclera and 8 hours in cornea. The changes of concentration of 125I-NGF in group B showed normal curve change. The peak time in group B were all 6 hours in all the tissues except aqueous humor (3 hours). Except the high concentration in vitreous body caused by intravitreal injection, the concentration of 125I-NGF in retina was the highest in group A. Conclusion Intravitreal injection of 125I-NGF can gain higher concentration in each ocular tissue than posterior juxtascleral injection, especially in retina. So intravitreal injection of NGF is a better ocular delivery method to treat the ocular fundus diseases.