BACKGROUND: Biological aging (BA) trajectory can capture the characteristics of the dynamic process of aging. Although toxic metals were associated with various health effects, there was limited study of their single and joint effects on BA trajectory. METHODS: A total of 2688 community-based older adults (≥65 years) were enrolled in this study, and we measured a composite BA indicator based on 9 clinical and anthropometric measures using Klemera and Doubal methods at four time points from baseline to the last follow-up. Group-based trajectory modeling was used to identify the aging trajectories. The associations between toxic metals and BA trajectories were analyzed by multivariable multinomial logistic regression. Quantile g-computing was used to explore the mixed effect of toxic metals. Pairwise interactions of toxic metals were further assessed. RESULTS: Three BA trajectories including slow aging, normal aging, and accelerated aging were identified in this study. Quantile g-computing showed toxic metals mixture was associated with higher risk of being in normal aging trajectory (OR = 1.14, 95%CI: 1.01, 1.29) or accelerated aging trajectories (OR = 1.53, 95%CI: 1.25, 1.88), with Pb as the dominant contributor. An interquartile range (IQR) increase in ln-transformed Pb was associated with an increased risk of being in normal aging (OR = 1.21, 95%CI:1.08, 1.35) or accelerated BA trajectory (OR = 1.54, 95%CI:1.31, 1.82) compared with slow aging trajectory. Similarly, per IQR increase in As was associated with a higher risk of being in accelerated BA trajectory (OR = 1.18, 95%CI: 1.01, 1.39). The interaction between toxic metals exposure was not significant. CONCLUSION: This study identified three BA trajectories and found the association between mixed toxic metals and increased risk of accelerated BA trajectories, with Pb as the dominant contributor. These findings highlight the importance of reducing toxic metals in the environment and may assist in developing effective anti-aging interventions in older adults.