Objective To explore the correlation between the level of pain catastrophizing and self-efficacy and the recovery of knee function after total knee arthroplasty （TKA）. Methods The clinical data of 124 patients who underwent TKA at the First Affiliated Hospital of Anhui Medical University from January 2021 to June 2025 were retrospectively collected. These data included general information， postoperative pain catastrophizing scale scores， rehabilitation self-efficacy scale scores， and knee joint function. Pearson correlation analysis was conducted to analyze the relationships between the levels of pain catastrophizing and rehabilitation self-efficacy and the recovery of knee joint function after TKA. Structural equation modeling was utilized to examine the mediating effect of rehabilitation self-efficacy between patients' pain catastrophizing and the recovery of knee joint function. Based on the recovery of knee joint function after surgery， the patients were divided into the good recovery group and the poor recovery group. The clinical data and the results of various scales were compared between the two groups. Multivariate logistic regression analysis was applied to screen the influencing factors of knee joint function recovery after surgery. Results The total score of the postoperative Pain Catastrophizing Scale （PCS） for 124 patients was （31.74 ± 4.90） points. The total score of the Self-Efficacy for Rehabilitation Scale （SER） was （81.03 ± 10.86） points， and the total score of the Hospital for Special Surgery Knee Score （HSS） was （77.32 ± 6.81） points. In TKA patients， the postoperative PCS scores， including those for exaggeration， helplessness， rumination， and the overall score， were negatively correlated with the scores of each dimension and the total score of the SER scale， as well as the total score of the HSS scale （P < 0.05）. The scores of each dimension and the total score of the SER scale were positively correlated with the total score of the HSS scale （P < 0.05）. The scores of each dimension of the PCS were positively correlated with the scores of each dimension of the SER scale （P < 0.05）. The PCS score had a direct negative impact on the HSS score （β = -0.762， 95%CI： -1.230 ? -0.392， P < 0.05）， and the PCS had an indirect negative impact on the HSS score through the SER （β = -0.199， 95%CI： -0.393 ? -0.020， P < 0.05）. The specific pathway： A significant increase in the PCS score led to a notable reduction in the SER score. Conversely， a significant increase in the SER score substantially enhanced the HSS score （β = 0.194， 95%CI： 0.037 ? 0.351， P < 0.05）. The overall negative effect of PCS on HSS was significant （P < 0.05）. Among the total negative impact of PCS on HSS， 21.90% was realized through the mediating pathway of reducing SER， and SER played a partial mediating role between PCS and HSS. Out of the 124 patients， 86 cases （69.35%） exhibited good recovery 4 weeks after surgery， whereas 38 cases （30.65%） showed poor recovery. The poor-recovery group had a higher proportion of patients who were over 60 years old， widowed， and self-funded compared to the good-recovery group （P < 0.05）. The PCS score in the poor-recovery group was higher， while the SER score was lower （P < 0.05）. Being over 60 years old and having a PCS score ≥ 30 points were risk factors for poor knee joint function in patients after TKA （P < 0.05）， while high SER scores were a protective factor （P < 0.05）. Conclusions Patients who have undergone TKA exhibit a relatively high level of postoperative pain catastrophizing and a moderate level of rehabilitation self-efficacy. Both of these factors are associated with the recovery of knee joint function after surgery. The level of pain catastrophizing can directly influence the recovery of knee joint function in TKA patients and can also indirectly impact it through the mediating effect of rehabilitation self-efficacy. Being over 60 years old and having high PCS scores are risk factors for poor knee joint function recovery after TKA， whereas high SER scores are protective factors.