Diabetes mellitus (DM) is one of the fastest growing chronic diseases in the world and one of the main causes of vision loss. Whether or not diabetic choroidopathy (DC) is involved in the initiation and progression of diabetic ocular complications needs to be explored. We included 54 diabetic eyes from 36 diabetic patients, and 54 healthy eyes from 32 control subjects after propensity scores matching. All of the subjects were given pupil light and dark adaptation examination and optical coherence tomography angiography (OCTA). Scotopic pupil diameter (SPD), pupil contraction amplitude, and velocity of pupil contraction of the diabetic group were significantly lower than that of the healthy control group (P <0.05). Choroidal thickness at temporal quadrant (at 750 mu m) and superior quadrant (at 1500 mu m and 2250 mu m) increased in diabetic group compared to control group(P <0.05). In the diabetic group, choriocapillaris blood flow signal density (CCBFSD) in the macular area (diameter= 2000 mu m) were significantly decreased compared with the healthy control group (P <0.05). Apparent changes in pupil and choroidal blood flow were observed in the diabetic patients.