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Objective To investigate the correlation between the severity of diabetic peripheral neuropathy (DPN) and dry eye disease in patients with type 2 diabetes mellitus (T2DM). Methods A cross-sectional study was conducted on 120 T2DM patients (240 eyes) admitted in our hospital from July 2020 to July 2021. According to the neuropathy disability score (NDS), the subjects were divided into non-DPN group (n=40), mild DPN group (n=40), and moderate to severe DPN group (n=40). Dry eye disease examinations were subsequently performed, including ocular surface disease index (OSDI) scale, tear film break up time (BUT), Schirmer Ⅰ test (SⅠt), and corneal fluorescein staining (CFS) scoring. In addition, corneal nerve parameters, such as corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), corneal nerve fiber length (CNFL) and corneal nerve tortuosity (CNT) were measured by corneal confocal microscopy. The corneal nerve parameters, as well as prevalence and indicators of dry eye disease were compared among all the groups, and the correlation of NDS with corneal nerve parameters and tear quality were analyzed. Results Examination results showed that the more serious DPN was, the lower the CNFD, CNBD and CNFL were (P < 0.05), and CNT in the moderate to severe DPN and mild DPN groups was significantly higher than that in the non-DPN group (P < 0.05). The prevalence of dry eye was greatly increased in the moderate to severe DPN group (62.5%), as compared with the non-DPN group (27.5%) and mild DPN group (30.0%) (P < 0.05). OSDI score was also notably elevated in the moderate to severe DPN group in comparison with the other 2 groups (P=0.004, P=0.023). Moreover, the moderate to severe DPN group had lower SⅠt (P=0.010) while higher CFS score (P=0.008) than the non-DPN group. It was found that the higher the NDS was, the lower volume of tear secreted (r=-0.316, P=0.001); and the greater the CNT was, the less stable tear film became (r=-0.261, P=0.004). In addition, the tear production was reduced with the lower CNFD, the less CNBD, the shorter CNFL, and the higher CNT, respectively (r=0.202, P=0.021; r=0.224, P=0.014; r=0.262, P=0.004; r=-0.193, P=0.034). Conclusion Patients with moderate and severe DPN have a high prevalence of dry eye disease and an increased OSDI score. Patients with higher DPN severity score (NDS) have lower tear secretion.