Objective To explore the developmental trajectories and bidirectional relationship between personal mastery and illness perception in patients after total hip arthroplasty, and to provide evidence for targeted psychological intervention. Methods By convenience sampling, 290 patients undergoing primary total hip arthroplasty were recruited from 4 tertiary hospitals in Urumqi from August to December 2024.The general information questionnaire, the Personal Mastery Scale and Brief Illness Perception Questionnaire were administered at 1-2 days before discharge, and 1, 3, 6 months after surgery. Results Personal mastery was divided into four trajectory subgroups:low mastery-improving, low mastery-rapid rising, moderate mastery-fluctuating, and high mastery-slow rising.Illness perception was classified into three trajectories:low perception-stable, moderate perception-rapid declining, and high perception-gradually slowing.Dual-trajectory analysis showed 25.86% of patients belonged to both high mastery-slow rising and moderate perception-rapid declining groups; 85.19% of low mastery-improving patients were in the high perception-slow declining group; 88.64% of low perception-stable patients fell into the high mastery-slow rising group. Conclusion The improvement of personal mastery is significantly correlated with the reduction of illness perception after total hip arthroplasty.Clinical staff should dynamically monitor patients′ personal mastery and illness perception, and implement comprehensive interventions to optimize psychological and physical rehabilitation as well as long-term outcomes.