AIM: To optimize the technique of intravenous injection of Evans blue and retinal preparations in mice, improving the accuracy and repeatability of staining experiment of retinal preparations.METHODS: C57BL/6 male mice were intravenous injected with 10g/L(1%)Evans Blue 0.3mL and circulated in vivo for 10 or 20min, and the eyes were removed after sacrificed and fixed in 4% paraformaldehyde for 20, 40 or 60min. When failure of intravenous injection, the experiment was remediated by intraperitoneal injection of 1% Evans Blue 0.3mL, circulated in vivo for 3h and fixed for 60min to observe morphology, distribution and leakage of the retinal vessels. Besides, we compared the morphology, distribution and leakage of the retinal vessels after intravenous injection with those after intraperitoneal injection to determine the optimal conditions for in vivo circulation time and retinal preparations.RESULTS: After intravenous injection, compared to the retinal vascular condition under 20min in vivo circulation time of Evans blue and 20 or 40min of fixation, with 10min of in vivo Evans blue circulation and 60min of fixation, the morphology of retinal vascular was more intact with less retinal vascular leakage, and the vascular branches are clear. When intravenous injection failed, remediated results from intraperitoneal injection showed that the morphology and distribution of retinal vessels were intact. There was no significant difference in morphology, distribution and leakage of the retinal vessels after 3h of intraperitoneal Evans blue circulation compared to 10min intravenous Evans blue circulation.CONCLUSION: This experiment optimizes the protocol, improves the accuracy and reproducibility of retinal preparations, and provides a reference for the study of related retinal vascular diseases.