Objective: To investigate the association of weight-adjusted waist index (WWI) and its changes with cardiovascular and cerebrovascular diseases (CCVD) mortality risk in adults in China. Methods: Data collected from the China Chronic Disease and Risk Factor Surveillance in 2010 were used as baseline data. A total of 60 surveillance areas (25 urban ones, 35 rural ones) in 11 provinces were selected for the follow-up study. After excluding those with pre-existing CCVD at baseline survey, a cohort of 36 173 participants was established. The first follow-up from 2016 to 2017 was conducted to collect the morbidity and mortality data of CCVD in the study participants by using questionnaires. At the second follow-up in 2022, deaths from CCVD were tracked at 60 surveillance areas by interfacing with the database of the National Cause of Death Surveillance System. Multifactor logistic regression model was used to analyze the association between WWI and the risk for CCVD mortality; Cox proportional hazards regression model was used to analyze the association between the change of WWI and the risk for CCVD mortality. All the analyses were stratified by baseline characteristics, including age and sex. Diabetes patients were excluded from the sensitivity analyses. Results: A total of 36 039 study participants were included in the analysis on the association between WWI and the risk for CCVD mortality, and 711 CCVD deaths were observed. A total of 7 107 study participants were included in the analysis on the association between changes of WWI and the risk for CCVD mortality, and 96 CCVD deaths were observed. After adjusting for relevant confounders, the analysis revealed a significant positive association between WWI and CCVD mortality. Each 1-unit increase in WWI was associated with a 18% increase of risk for CCVD mortality (OR=1.18, 95%CI: 1.07-1.31). Furthermore, the participants in the Q4 group showed a 29% higher CCVD mortality risk compared with those in the Q1 group (OR=1.29, 95%CI: 1.03-1.62), showing a dose-response relationship. The results of the association analysis between changes in WWI and the risk for CCVD mortality showed that the risk for CCVD mortality was 1.52 times higher in the T3 group than in the T1 group (HR=1.52, 95%CI: 1.12-2.08). Subgroup analyses revealed no significant interaction effects. Sensitivity analyses showed stable results. Conclusions: WWI is a crucial indicator in evaluating the risk for mortality CCVD. Increased WWI and higher level of WWI change might be the significant predictors of CCVD mortality risk.