Objective: To investigate the prospective association between the baseline Atherogenic Index of Plasma (AIP) and the risk of incident chronic liver disease (CLD) in Chinese adults aged 45 years and above. Methods: This study utilized data from the China Health and Retirement Longitudinal Study (CHARLS) from 2011 to 2018. A total of 6,425 participants free of CLD at baseline were included. AIP was calculated as log(triglycerides/high-density lipoprotein cholesterol). Modified Poisson regression models were used to calculate the risk ratio (RR) and 95% confidence interval (CI) for the association between AIP (as a continuous variable and in quartiles) and incident CLD (ascertained by self-report of physician diagnosis, excluding fatty liver, liver tumor, or cancer). Restricted cubic splines (RCS) were employed to examine the dose-response relationship. Results: During a follow-up of 7 years, 345 incident CLD cases were documented. After multivariable adjustment, each unit increase in AIP was associated with a 58% higher risk of CLD (RR=1.58, 95% CI: 1.20~2.10). Compared with participants in the lowest AIP quartile (Q1), those in the highest quartile (Q4) had a 50% increased risk of CLD (RR=1.50, 95% CI: 1.12~2.01), with a significant increasing trend across quartiles (P for trend=0.003). RCS analysis revealed a linear positive association between AIP and CLD risk (P for non-linearity=0.940). Subgroup analyses showed that the association was consistent across groups defined by sex, age, BMI, and metabolic risk factors. Conclusion: An elevated AIP is independently and linearly associated with an increased risk of CLD among community-dwelling middle-aged and older Chinese adults. As a simple composite lipid index derived from routine tests, AIP may be useful for identifying individuals at high risk for CLD.