Objective:We applied fluorescein fundus angiography (FFA) to analyze diagnostic criteria of fibrovascular proliferative membranes of diabetic retinopathy (DR) Ⅳ~Ⅴ period, and to observe different parts, shape, and the effects of different sizes of fibrovascular membrane photocoagulation. Methods: A total of 98 eyes from 56 patients with DR Ⅳ~Ⅴ period were analyzed in this study. FFA was performed to evaluate the above-mentioned 56 cases in the general situation of the retina and specified the panretinal photocoagulation treatment. During follow-up of 6 months, the patients were examined by FFA and routine inspection in the 1st, 3rd and 6th months, respectively. According to treatment effects, the 56 cases were divided into two groups:the effective treatment group and the ineffective treatment group. The result of pre-treatment FFA was analyzed and different parts, shapes as well as the treatment effect of different sizes of fibrovascular membrane photocoagulation were observed. Results: A total of 98 eyes from 56 patients were selected. The effective treatment group included 72 eyes and the ineffective treatment group included 26 eyes. The efficiency was 73.5%. There were 18 eyes undergoing vitrectomy and 2 eyes became neovascular glaucoma. According to the results of pre-treatment FFA, we compared and observed the fibrovascular membrane of the two groups. There was a significant difference of angiogenesis of merged optic disc between the two groups (P < 0.05). Furthermore, there was a significant difference of fibrovascular membrane range between the two groups (P < 0.05). Also, the difference of diffuse film membrane and bridge-shaped membrane between the two groups was significant (P < 0.05). Conclusion: The analysis of different parts, shapes and sizes of fibrovascular membranes by FFA has the guiding significance to panretinal photocoagulation treatment and vitrectomy.