The therapeutic effect of sustained intravitreal injectable voriconazole microspheres (VCZ-MS) on an experimental endophthalmitis of Aspergillus fumigatus was investigated. VCZ-MS was prepared successfully and its physico-chemical property was also evaluated. Right eyes of albino rabbits were infected with an intravitreal injection of 1 000 CFU x mL(-1) of susceptible Aspergillus fumigatus. All fungal endophthalmitis models were randomly divided into five groups 48 hours later: Group A is control group with no treatment; in group B, vitrectomy was performed combined with intravitreal 3 times injections of 100 microg x 0.1 mL(-1) voriconazole every other day. In group C, D and E, vitrectomy was performed combined with intravitreal injection of 0.5 mg, 1.0 mg and 1.5 mg VCZ-MS respectively. The treatment effect was assessed by slit lamp and indirect ophthalmoscope funduscopy examination, using clinical grading system of inflammation in the anterior chamber and the vitreous opacity. The optical microscopy revealed that microspheres obtained from the experiment design were opaque, discrete and spherical particles with smooth surfaces. The drug content and encapsulation efficiency of microspheres were 29.94% and 73.5%, respectively. Endophthalmitis occurred in all eyes of group A, and rapidly developed to panophthalmitis. The inflammation grade of group B, C, D or E was lower than that of group A (P < 0.05). The grade of vitreous opacity in group C, D, E is lower than group B (P < 0.05). Two eyes in group C developed to panophthalmitis. But in group D and E, all eyes whose inflammation was controlled had no recurrence with vitreous clear. Histopathological examination showed normal structures in the cured eyes, while most uncured eyes were atrophic and with eyeball destroyed. So, it can be safely concluded that the curative effect of intravitreal VCZ-MS is significantly better than that of routine intraocular injection of voriconazole. The optimal dose is the one containing 1.0 mg voriconazole.