Background Sarcopenia is a global challenge and a potential modifiable risk factor for cardiorenal diseases. However, the geospatial variation of sarcopenia in China and its region-specific associations with cardiovascular disease (CVD) and chronic kidney disease (CKD) remain poorly defined.Methods We analyzed participants aged over 45 years from the China Health and Retirement Longitudinal Study (CHARLS, 2011–2020). Sarcopenia was defined by AWGS 2019 criteria. Spatial autocorrelation analysis (Moran's I) identified provincial clustering. Region-stratified longitudinal logistic regression assessed associations between baseline sarcopenia and incident CVD and CKD during a median 9.0-year follow-up.Results Among 12,263 participants (52.1% female; 27.4% aged over 65), spatial autocorrelation analysis identified significant 'High-High' sarcopenia clustering in Southwest China (P < 0.05), contrasting with 'Low-Low' clustering in Northern and Northeastern China (P < 0.05). In Southwest China, baseline sarcopenia was significantly associated with increased risk of incident CVD (OR 1.58, 95% CI 1.08–2.32, P < 0.05) and CKD (OR 1.76, 95% CI 1.17–2.63, P < 0.01). Notably, these longitudinal associations were not statistically significant in national-level analyses (CVD: OR 1.11, P = 0.40; CKD: OR 1.28, P = 0.09) or other regions.Conclusions This study provides the first national sarcopenia atlas for China, revealing significant geographic clustering and region-stratified associations with cardiorenal diseases. The increased risk specifically in Southwest China highlights the necessity for region-specific public health strategies and resource allocation for sarcopenia management.