Background <p>Community-dwelling older adults residing in non–age-friendly external environments face a higher risk of restricted life-space mobility. Although improving the external environment may help mitigate this risk, environmental interventions are often complex, challenging to implement, and demonstrate limited effectiveness. Enhancing intrinsic capacity, however, may offer a novel approach to addressing the risk of restricted life-space mobility in older adults.</p> Objectives <p>This study aims to examine the relationships among the external environment, intrinsic capacity, and life-space mobility, while also analyzing the mediating role of intrinsic capacity between the external environment and life-space mobility.</p> Methods <p>From March to June 2024, a cross-sectional study was conducted using a multistage sampling method involving 808 community-dwelling older adults aged 60 years and above in Yanji, Jilin Province, China. Data were collected using standardized instruments, including a general information questionnaire, the Life-Space Assessment for older adults, the Intrinsic Capacity Assessment Tool, and the External Environment Assessment Tool. All data were analyzed using SPSS 28.0. Pearson correlation analysis was performed to explore the relationships between variables, and mediation analysis was conducted using Model 4 in the PROCESS macro for SPSS.</p> Results <p>The incidence of limited life-space mobility was 55.4%, with life-space mobility score of 60.00 ± 30.76, an intrinsic capacity score of 180.10 ± 29.12, and an external environment score of 80.40 ± 17.82. Pearson correlation analysis revealed that life-space mobility was positively correlated with both the external environment and intrinsic capacity, with correlation coefficients of 0.721 and 0.622, respectively (<i>P</i> &lt; 0.01). Additionally, the external environment was positively correlated with intrinsic capacity, yielding a correlation coefficient of 0.699 (<i>P</i> &lt; 0.01). The mediation analysis results indicated a significant total association between the external environment and life-space mobility (B = 0.560, <i>t</i> = 16.875, <i>P</i> &lt; 0.001). The pattern of associations was consistent with partial mediation by intrinsic capacity, with a significant indirect path (Effect = 0.278, 95% <i>CI</i> [0.199, 0.355]), accounting for 22.35% of the total association.</p> Conclusions <p>The life-space mobility of older adults living in the community was moderately low. The external environment was associated with life-space mobility both directly and indirectly through intrinsic capacity. To improve the functional ability of community-dwelling older adults, attention should be given to enhancing their life-space mobility, optimizing the external environment, and strengthening intrinsic capacity. These efforts will contribute to achieving the goal of healthy aging.</p>