Objective This study aimed to investigate the impact of effort–reward imbalance on compassion satisfaction and compassion fatigue among clinical nurses working in high-pressure, high-demand environments, and to explore the potential psychological mediation mechanisms. Methods A convenience sample of 916 clinical nurses was recruited from three general hospitals in Shanxi Province, China, and relevant questionnaire data were collected. Ordinary least squares regression was applied to examine the overall effects of effort–reward imbalance on compassion satisfaction and compassion fatigue. Unconditional quantile regression was used to assess the heterogeneity of effects across different quantiles, and multiple mediation analysis was conducted to examine the indirect effects of rumination and psychological resilience. Results Linear regression showed that effort–reward imbalance was negatively associated with compassion satisfaction (β=-1.626,P<0.05) and compassion fatigue (β=-5.622, P<0.001). Unconditional quantile regression indicated that effort–reward imbalance was negatively associated with compassion satisfaction at the q42 - q48 quantiles (β=-2.560) and with compassion fatigue at the q5-q58 and q76-q97 quantiles. Multiple mediation analysis revealed significant indirect effects of effort–reward imbalance on compassion satisfaction via positive rumination, negative rumination, and psychological resilience, accounting for 21.6%, 35.2%, and 32.2% of the total effect, respectively. Effort–reward imbalance also exerted indirect effects on compassion fatigue through negative rumination and psychological resilience, in addition to a significant direct effect (β=-6.336,P<0.001). Conclusion The impact of effort–reward imbalance on nurses’ professional quality of life exhibits notable distributional heterogeneity. Mediation analyses highlight the importance of addressing cognitive regulation and psychological resources, suggesting that targeted psychological and cognitive interventions tailored to different risk groups may enhance nurses’ professional experience and psychological well-being.