Background Biological behavior of choroidal melanoma is closely related with angiogenesis.The microcirculation pattern in which tumor cells may be involved is different from neovascularization. Objective This study was to observe the microcirculation pattern of the choroidal melanoma tissue and analyze its relationship with the clinical pathology factor and the degree of cellular proliferation. Methods Forty-eight specimen of choroidal melanoma tissue were collected at Beijing Tongren Eye Centre from November 1997 through March 2006.Periodate acid Schiff staining was used to determine the microcirculation pattern of choroidal melanoma.The morphology of the tumor cells and the distribution of microcirculation pattern in the tumor were observed under a fluorescence microscopy with 544 nm wavelength,and the Ki-67 expression in the tumor was detected by immunochemistry.The relationships between the choroidal melanoma clinical pathology factor with Ki-67 expression and microcirculation pattern were evaluated by multiple stepwise regression model. Results A total of 9 kinds of microcirculation patterns were found by periodate acid Schiff staining.The occurring rate of loop- or network-like vascular pattern showed a significant elevation in the tumor tissue with epithelial cells in comparison with the tumor with spindle-like cells (66.7％ vs.30.6％ ) ( P=0.027 ).The expression rates of Ki-67 were 18.961 ± 10.995 and 19.481 ± 12.167 in the tumor tissue with loop- or network-like microvascular pattern,and those in the tumor tissue without loop- or network-like microvascular pattern were 10.261 ±5.669 and 12.021 ± 6.802,presenting significant differences between them ( P =0.000,P =0.010).Loop-like microvascular pattern was determined as the risk factor of the proliferation and metastasis of choroidal melanoma by multiple stepwise regression analysis (P=0.002). Conclusions Among the nine microcirculation patterns in choroidal melanoma,networks pattern is the most fashion,and Ki-67 expression is more strong in the tumor with epitheliod cells,suggesting that this microcirculation pattern is associated to the malignant degree and extent of proliferation in choroidal melanoma.