Abstract Purpose: Now, ultrasound-assisted precise localization in situ decompression has been widely used in the treatment of cubital tunnel syndrome. To compare with traditional open incision in situ decompression of cubital tunnel syndrome, we retrospectively analyze and compare the two methods. Methods: This retrospective study included 51 patients between 2018 and 2022. Patients are categorized by the treatment of cubital tunnel syndrome as follows: ultrasound-assisted precise localization in situ decompression (21 patients, cohort 1) and traditional open incision in situ decompression (30 patients, cohort 2). The Visual Analogue Scale (VAS), Vancouver Scar Scale (VSS), the modified Bishop score system, Aesthetic Appearance, preopertation Dellon\'s stage, and painkillers requirement are evaluated. In addition, operation time, hospital stay, complications and reoperation are recorded and compared. Results: In both cohorts, no significant differences are identified between them in the pre-opertation Dellon\'s stage, the modified Bishop score system, and the Visual Analogue Scale 6 weeks post operation. The aesthetic appearance, Vancouver Scar Scale, the Visual Analogue Scale post operation and the painkillers requirement of cohort 1 are better than those of cohort 2. The operation time and hospital stay in cohort 1 are significantly shorter. Cohort 1 had 5(23.80%) complications, including 1 case superficial infection, 1 case hematoncus,and 3 case incomplete decompression. Cohort 2 had 9 complications, including 2 case superficial infection, 2 case hematoncus and 5 case severe scar. The partial incomplete decompression cases in cohort 1 and 1 severe scar case in cohort 2 are treated with reoperation. Conclusion: Both procedures solve the vast majority of cubital tunnel syndrome and achieve a good recover. ultrasound-assisted precise localization in situ decompression performed better in operation time, hospital stay, aesthetic appearance, Visual Analogue Scale post operation, Vancouver Scar Scale, and the painkillers requirement. Traditional open incision in situ decompression decompress more thoroughly.