A digital healthcare system based on augmented reality (AR) has promising uses for postoperative rehabilitation. We compare effectiveness of AR-based and conventional rehabilitation in patients after rotator cuff repair (RCR). This study randomly allocates 115 participants who underwent RCR to digital healthcare rehabilitation group (DR group) and conventional rehabilitation group (CR group). The DR group performs AR-based home exercises using UINCARE Home+, whereas the CR group performs brochure-based home exercises. The primary outcome is a change in the Simple Shoulder Test (SST) score between baseline and 12 weeks postoperatively. The secondary outcomes are the Disabilities of the Arm, Shoulder and Hand (DASH) score; Shoulder Pain And Disability Index (SPADI) score; EuroQoL 5-Dimension 5-Level (EQ5D5L) questionnaire score; pain; range of motion (ROM); muscle strength; and handgrip strength. The outcomes are measured at baseline, and at 6, 12, and 24 weeks postoperatively. The change in SST score between baseline and 12 weeks postoperatively is significantly greater in the DR group than in the CR group (p = 0.025). The SPADI, DASH, and EQ5D5L scores demonstrate group×time interactions (p = 0.001, = 0.04, and = 0.016, respectively). However, no significant differences over time are observed between the groups in terms of pain, ROM, muscle strength, and handgrip strength. The outcomes show significant improvement in both groups (all p < 0.001). No adverse events are reported during the interventions. AR-based rehabilitation shows better improvement in terms of shoulder function after RCR compared to conventional rehabilitation. Therefore, as an alternative to the conventional rehabilitation, the digital healthcare system is effective for postoperative rehabilitation.