Objective: To investigate the effect of salt intake on lens opacity in type 2 diabetes mellitus patients in cold region of Northern China. Methods: This study selected 2 069 inpatients with type 2 diabetes mellitus who were treated in Department of Endocrinology of the First Affiliated Hospital of Harbin Medical University and the Diabetes Branch of Mudanjiang Cardiovascular Hospital from October 2016 to November 2018. After the exclusion criteria, 1 548 subjects were included in the statistical analysis. According to the results of slit lamp examination they were divided into two groups. There were 894 patients in the non-opacity group and 654 patients in the lens opacity group. All participants underwent general information, medical history collection, physical examination, 24-hour urine sodium, blood biochemistry and other indicators, then analyzed the correlation with lens opacity. Results: This is a cross-sectional study. Multivariate logistic regression analysis showed that 24-hour urine sodium ≥128.05 mmol is a risk factor for lens opacity in this study (128.05–175.50 mmol: OR=1.784, 95% CI 1.045–3.044, P<0.05; 175.51–237.10 mmol; OR=2.488, 95% CI 1.47–4.211, P<0.01; 24-hour urine sodium ≥237.11 mmol: OR=2.301, 95% CI 1.373–3.858, P<0.05). Age ≥50 years is also a risk factor for lens opacity (50 years ≤ age <60 years: OR=2.375, 95% CI 1.126–5.007, P<0.05; 60 years ≤age <70 years: OR=5.336, 95%CI 2.522–11.291, P<0.01; age ≥70 years: OR=6.773, 95% CI 2.376–19.306, P<0.01). Diastolic blood pressure ≥90 mmHg is a protective factor for lens opacity (OR=0.578, 95% CI 0.376–0.889, P<0.05); HbA1c% level affects lens opacity (OR=1.523, 95%CI 1.01~2.299, P<0.05). Conclusion: Salt intake is still higher than the dietary salt intake recommended by WHO in cold area of northern China. High salt intake is significantly correlated with lens opacity, which may become a low-cost new thought in delaying the onset and development of cataract in type 2 diabetes mellitus patients.