Objective To evaluate the influence of the location of retinal vessel trunk on neuroretinal rim width of inferior and superior sectors of optic disc, and explore its role in the diagnosis of glaucomatous optic nerve lesion. Methods The photographs of ocular fundus from 459 patients with clear location of retinal vessel trunk, including large disc in 131, medium disc in 145, horizontally oval disc in 75, and small disc in 108 were evaluated. Independent-sample t test was used to compare the difference of the superior and inferior rim widths between the higher-vessel group and the lower-vessel group, and to compare the difference of superior and inferior vessel distances between the narrow-superior-rim-width group and the narrow inferior-rim-width group. Results In most of the patients, or the ones with large and small disc, the ratio of superior rim width to summation of superior and inferior rim widths in the higher-vessel group（0.467plusmn;0.051，0.445plusmn;0.040，0.508plusmn;0.056）were less than which in the lowervessel group（0.500plusmn;0.066，0.474plusmn;0.062，0.546plusmn;0.048）, and the differences were significant（P=0.000, 0.045, 0.018）; the ratio of superior vessel distance to summation of superior and inferior vessel distance in the narrow-superior-rim-width group（0.510plusmn;0.051，0.508plusmn;0.055，0.512plusmn;0.036）were less than which in the narrow-inferior-rim-width group（0.528plusmn;0.045，0.533plusmn;0.048，0.534plusmn;0.045）, and the differences were significant（P=0.000, 0.046, 0.022）. Conclusions The position of optic disc vessel trunk influences its superior and inferior rim width. The rim closer to vessel trunk position has narrower width than which comparatively far away from the position. In patients with large, medium, horizontally oval optic disc, glaucoma optic nerve lesion would be considered if the optic disc has the shape of narrower inferior rim, broader superior rim, and vessel location in the superior half of the disc. In the ones with small disc, the optic disc with the shape of narrower superior rim, broader inferior rim, and vessel location in the inferior half of the disc may suggest glaucoma optic nerve lesion. (Chin J Ocul Fundus Dis, 2007, 23: 118-121)