Abstract： Objective To investigate the change of contrast sensitivity (CS) test combined with the clinical value different kinds of electro-Physiological in sub-clinical stage of diabetic retinopathy,and find some more objective and sensitive parameters in early diagnosis of diabetic retinopathy (DR). Methods Selected 59 patients (118 eyes) with type Ⅱ diabetes mellitus (DM) diagnosed by Department of Endocrinology,were divided into three groups by ophthalmoscopy and fundus fluorescein angiography,including 40 eyes without diabetic retinopathy (NDR),38 eyes with background DR (BDR) and 40 eyes with proliferative DR (BDR),16 cases (32 eyes) of normal controls group had also been taken,to compare the difference of the CS,F-ERG,P-VEP between four groups. Results There were significant differences between the normal control group and the DM group in CS:The differences in middle frequency were significant (P ＜0.05) difference between NDR and normal group,low frequency and high frequency were significant (P ＜0.05) difference between BDR and normal group,each spatial frequency were significant (P ＜0.05) difference between PDR and normal group.The b-wave latency of F-ERG were significant (P ＜0.05) difference between normal control group and NDR,BDR,PDR group.The b-wave amplitude of F-ERG were no significant (P ＞0.05) difference between diabetic groups.The P100 wave latency of P-VEP were significant (P ＜0.001) difference between normal control group and NDR,BDR,PDR group.As of the further development of diabetic retinopathy,the P100 wave latency of P-VEP was significantly delayed but had no significant difference.The P100 wave amplitude of P-VEP in diabetic retinopathy decreased but was not obvious.Latency change rate in b-wave of F-ERG were greater than P100 wave latency of P-VEP in DR groups. Conclusions Contrast sensitivity,F-ERG and P-VEP has changed in patient with sub-clinical stage of diabetic retinopathy.Contrast sensitivity combined with P-ERG is sensitive parameters in diagnosis of early diabetic retinopathy.