ObjectiveTo investigate the temporal trend of weight-adjusted-waist index （WWI） and its association with the risk of incident cardiovascular diseases （CVD） among middle-aged and older Chinese adults. MethodsBased on the China Health and Retirement Longitudinal Study （CHARLS）， this research enrolled participants aged 45 and above with complete physical measurement data from the 2011， 2013， and 2015 waves. Complex sampling weights were applied to calculate the mean WWI， and the Mann-Kendall test was used to analyze its trend. From the 2011 baseline survey， individuals with a history of cardiovascular disease or missing key covariates were further excluded. New-onset cardiovascular outcome events were collected during follow-up until 2020. Participants were categorized into Q1–Q4 groups based on baseline WWI quartiles. Multivariable log-binomial regression models were constructed to assess the association between WWI and CVD， while restricted cubic splines were employed to evaluate potential nonlinear relationships. Sensitivity analyses were conducted to verify the robustness of the findings. ResultsFrom 2011 to 2015， the weighted mean WWI among Chinese middle-aged and older adults remained generally stable （2011： 11.17±1.68； 2013： 11.28±1.35； 2015： 11.24±1.59； P for trend <0.05）. During the longitudinal follow-up， 1 784 incident CVD cases were documented. After multivariable adjustment， each unit increase in WWI was associated with a 17% increased risk of CVD （RR： 1.17， 95%CI： 1.10-1.24）. Compared with the Q1 group， the risk of CVD in the Q2， Q3， and Q4 groups increased by 23% （RR： 1.23， 95% CI： 1.07-1.40）， 27% （RR： 1.27， 95% CI： 1.11-1.44）， and 40% （RR： 1.40， 95% CI： 1.22-1.60）， respectively. A significant linear trend was observed between the increasing WWI and elevated CVD risk （P for trend <0.001）. Subgroup analysis revealed a stronger association in participants aged 45-60 years （P for interaction <0.05）. The results of sensitivity analysis were consistent with the main research results. ConclusionsThe overall trend of WWI level in the middle-aged and elderly population in China is stable from 2011 to 2015. The higher level of WWI is associated with an increased risk of CVD， suggesting that WWI may be used as a simple and effective indicator to evaluate the risk of cardiovascular metabolism in middle-aged and elderly people.