Evaluation of RC28-E Injection in Diabetic Retinopathy

Inclusion Criteria: * Sign the consent form, willing and able to comply with clinic visits and study-related procedures; * Aged 18 years to 80 years, male or female; * Diabetes mellitus(type 1 or 2); * Moderately severe to severe NPDR (DRSS levels 47 or 53) which was confirmed by the central reading center, and in whom PRP can be safely deferred by the investigator's judgement; * BCVA score in the study eye of ≥69 letters (approximate Snellen equivalent of 20/40 or better) using the ETDRS protocol at an initial testing distance of 4 meters; * If both eyes meet the inclusion criterion, one eye with poor BCVA is selected as the study eye; Exclusion Criteria: * Presence of DME threatening the center of the macula (within 1,000 microns of the foveal center) in the study eye; * Evidence of retinal neovascularization on clinical examination or FA; * Any prior focal or grid laser photocoagulation (within 1,000 microns of the foveal center) or PRP in the study eye; * Current ASNV, vitreous hemorrhage, tractional retinal detachment or epiretinal membrane involved the macular in the study eye; * History of vitreoretinal surgery in the study eye; * Active infectious blepharitis, keratitis, scleritis, conjunctivitis at the screening assessments in either eye ; * Previous treatment with anti-angiogenic drugs in either eye or system (ranibizumab, aflibercept, conbercept, etc) within 3 months of the Day 0 visit; * Previous use of intraocular or periocular corticosteroids (such as triamcinolone acetonide, dexamethasone vitreous implant) in either eye within 6 months of day 0. * Uncontrolled clinical disease (such as severe psychiatric, neurological, cardiovascular, respiratory disease or other systemic diseases) and tumors; * Pregnant or lactating women, subjects who had family planning throughout the study period; * Those who participated in clinical trials for 3 months or 5 half-lives of the investigational product (the longer the time) before theDay 0 * Those who considered unsuitable for enrollment by investigator.