Objective:To evaluate the value of ultra-widefield scanning laser ophthalmoscopy (UWFSLO) for screening diabetic retinopathy (DR).Methods:A cross-sectional study was conducted.A total of 1 288 patients (2 304 eyes) with type 2 diabetes who underwent the screening of DR were selected in Kailuan Rehabilitation Hospital in Tangshan City, Hebei Province from October 2016 to December 2016.The general information and medical records were collected.Patients completed fundus inspection by both UWFSLO and two-field 45° horizontal digital color fundus photography.The effective retinal images of the two methods were analyzed and the detection and grading of DR were compared between the two methods.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Kailuan (Group) Co., Ltd.Hospital (No.2006-5).Written informed consent was obtained from each subject.Results:After excluding the unclear and missing images, 1 857 eyes were finally included in this study.The detection rates of DR by color fundus photo, UWFSLO pseudocolor image and green channel image were 31.3%(581/1 857), 44.5%(826/1 857), and 43.4%(807/1 857), respectively, with a statistically significant difference ( χ2=85.547, P<0.001).The detection rates of DR by UWFSLO pseudocolor image and green channel image were higher than that by color fundus photo, and the differences were statistically significant (both at P<0.001).The agreement between UWFSLO and two-field 45° horizontal digital color fundus photography for grading DR severity was moderate with a Kappa value of 0.375 ( P<0.001) and a complete agreement of 64.08%.The UWFSLO green channel image and pseudocolor images had excellent consistency for grading DR severity with a Kappa value of 0.953( P=0.008) and complete agreement of 98.17%.The detection rates of microaneurysm (MA), intraretinal microvascular abnormalitie (IRMA) and neovascularization (NV) by UWFSLO pseudocolor images were lower than that by green channel images, showing statistically significant differences ( Z=-16.489, -4.198, -2.111; all at P<0.05). Conclusions:UWFSLO has better detection and grading of DR than two-field 45° horizontal digital color fundus photography, and green channel images are better at detecting MA, IRMA, and small NV lesions.UWFSLO has good application value in the screening and diagnosis of DR in large populations.