Objective: The distal transradial access (dTRA) is a new access for Coronary angiography (CAG) and percutaneous Coronary intervention (PCI). The distal radial artery diameter is smaller than the radial artery diameter. At present, there are very few studies about the diameter of the distal radial artery. Methods: This is a cross-sectional single-center study. A total of 106 hospitalized patients were included. The distal radial artery diameters of the left hand of all patients were measured. Clinical and ultrasound data were collected. Results: The mean of the distal radial artery diameter of all patients was 2.0586 ± 0.33 mm. According to the mean, the patients were divided into two groups——diameter ≥ 2.0586 mm group and diameter < 2.0586 mm group. By comparing the two groups, the related factors and independent predictors of the distal radial artery diameter ≥ 2.0586 mm were obtained. Male gender, height ≥ 160 cm, weight ≥ 63 kg, body mass index (BMI) ≥ 24 kg/m2, and body surface area (BSA) ≥ 1.6573 m2 were related factors. Male gender and BMI ≥ 24 kg/m2 were independent predictors. Conclusions: Male gender and BMI ≥ 24 kg/m2 patients may have a larger distal radial artery diameter.