Rehabilitation training after total knee arthroplasty (TKA) is crucial for restoring joint function. This quasi-experimental enrolled 82 orthopedic patients from a Grade A tertiary hospital in Yunnan Province, who were divided into a control group (41 cases) and an experimental group (41 cases). Both groups received routine nursing care, while the experimental group additionally received a 3-month rehabilitation program based on the Health Action Process Approach (HAPA) theory combined with the best evidence for TKA rehabilitation. Preoperative indicators showed no significant difference in preoperative indicators between the two groups. Postoperatively, the experimental group demonstrated higher Hospital of Special Surgery (HSS) scores and Self-Efficacy for Rehabilitation Outcome Scale (SER) scores (P-adjusted = 0.020;P-adjusted = 0.006), as well as lower Numerical Rating Scale (NRS) scores and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores (P-adjusted = 0.009, P-adjusted = 0.016). The research found that a rehabilitation program based on the HAPA theory is both scientific and effective, which can significantly relieve pain, improve joint function, and enhance patients' self-efficacy in rehabilitation.