Objective To explore the trends and influencing factors of social participation in young and middle-aged patients after liver cancer surgery, aiming to provide a reference for taking targeted interventions to facilitate their smooth return to society. Methods A longitudinal study was conducted with 190 young and middle-aged liver cancer patients. Their social participation was assessed using the Utrecht Scale for Evaluation of Rehabilitation-Participation (USER-P) preoperatively, 1 month and 3 months after surgery. Data on demographics, disease-related factors, psychological variables (depression, anxiety, fear of disease progression, resilience), family functioning, and social support were collected. A linear mixed-effects model was used to analyze the influencing factors of social participation. Results The social participation frequency scores before surgery, at 1 month after surgery, and at 3 months after surgery were (31.47±8.88), (30.30±9.34), and (31.33 ± 9.30), respectively. The scores for participation restrictions were (85.71±9.08), (83.76±11.06), and (84.04±10.67), and for participation satisfaction were (50.49±12.50), (50.75±11.87), and (52.07±10.57), respectively. The linear mixed-effects model indicated that place of residence, employment status, time since diagnosis, anxiety, and fear of disease progression were the main influencing factors of social participation (all P<0.05). Conclusion Young and middle-aged liver cancer patients report low frequency of social participation after surgery with less restrictions, and their participation satisfaction is at a low to moderate level. Many factors affect their social participation. Given the multiple factors affecting social participation, psychological interventions should be emphasized to support patients′ successful reintegration into society.