Objective:To investigate the effects of types of ulnar styloid process fracture on the treatment of distal radius fracture.Methods:The 80 patients were analyzed retrospectively who had been treated at The First Department of Hand Surgery, Honghui Hospital from January 2019 to January 2020 for fracture of distal radius complicated with fracture of ulnar styloid process. They were 25 males and 55 females, aged from 30 to 85 years (average, 58.6 years). According to the types of ulnar styloid process fracture, 40 patients were assigned into a Hauck type Ⅰ group and the other 40 into a Hauck type Ⅱ group. The 2 groups were compared in terms of operation, postoperative complications, hospital stay, bone union, visual analogue scale (VAS) on postoperative 1 to 3 days, and modified Mayo wrist function score, wrist range of motion and quality of life by WHOQOL-BREF at the last follow-up.Results:The 2 groups were comparable because there was no significant difference in age, gender, American Society of Anesthesiologists (ASA) rating, or time from injury to operation between them ( P>0.05). All the patients were followed up for 12 to 24 months (average, 17 months). There was no significant difference between Hauck type Ⅰ group and Hauck type Ⅱ group in operation time, intraoperative blood loss, hospital stay, rate of postoperative complications, fracture union, modified Mayo wrist function score or VAS on postoperative 1 to 3 days ( P>0.05). At the last follow-up, the palm tilt and ulnar inclination angles were 13.8°±1.9° and 21.6°±2.8° in Hauck type Ⅰ group, significantly larger than those in Hauck type Ⅱ group (11.9°±1.6° and 18.8°±2.3°) ( P<0.05). At the last follow-up, Hauck Ⅰ group scored 85.3±6.4,85.6±6.5, 84.7±6.3 and 85.0±6.7 respectively in the domains of physical health, psychology, environment and social relationships, significantly higher than those Hauck type Ⅱ group did (78.5±6.5, 78.9±6.5, 77.8±6.1 and 77.9±6.3) ( P<0.05). Conclusions:In open reduction and internal fixation for distal radius fracture, Hauck Type Ⅰ fracture of ulnar styloid process has no significant effect on the functional recovery of the wrist but Hauck Type Ⅱ fracture of ulnar styloid process may. Therefore, surgical fixation needs to be strengthened if Hauck Type Ⅱ fracture of ulnar styloid process is complicated.