Objective To analyze the trends in the burden of early-onset cancer attributed to overweight and obesity in China from 1990 to 2021 and to predicted its changes over the next 15 years,thus providing a reference for cancer prevention and control in China. Methods The data were sourced from the 2021 Global Burden of Disease database.The disease burden was described based on mortality rates,disability-adjusted life year (DALY) rates,and their age-standardized rates.R 4.4.1 software was used to analyze the differences and changes in disease burden across different gender and age groups.The Joinpoint regression model was adopted to quantify the temporal trends of the burden of early-onset cancer attributed to overweight and obesity in the Chinese population from 1990 to 2021,and the average annual percentage of change (AAPC) was calculated for age-standardized mortality rates and age-standardized DALY rates.An autoregressive integrated moving average model was established to predict changes in disease burden over the next 15 years. Results Between 1990 and 2021,the burden of early-onset cancers attributed to overweight and obesity in China showed an upward trend.The AAPC values of age-standardized mortality rates for men and women were 2.94% (95%CI=2.90-2.97) and 1.98% (95%CI=1.93-2.02),respectively,while those of age-standardized DALY rates were 2.88% (95%CI=2.83-2.91) and 1.82% (95%CI=1.77-1.86),respectively (all P<0.001).The age group of 30-34 years old in 2021 compared with 1990 saw the most significant increases (88.24% and 91.02%,respectively) in cancer mortality and DALY rates due to overweight and obesity.It was predicted that in the next 15 years,the age-standardized DALY rates for cancers (except female uterine cancer) attributed to overweight and obesity would keep rising.The top five cancers contributing to the disease burden in men would be colorectal cancer,liver cancer,leukemia,kidney cancer,and gallbladder and biliary tract cancer.For women,the top five cancers contributing to the disease burden in 2028 and earlier would be colon and rectum cancer,breast cancer,liver cancer,uterine cancer,and leukemia.From 2029 to 2036,ovarian cancer would surpass leukemia,rising to the fifth position. Conclusions From 1990 to 2021 and in the next 15 years,the burden of early-onset cancer attributed to overweight and obesity in China shows an overall upward trend.The main cancers causing the burden on men are colon and rectum cancer,liver cancer,leukemia,kidney cancer,and gallbladder and biliary tract cancer.The main cancers imposing the burden on women are colon and rectum cancer,breast cancer,liver cancer,uterine cancer,leukemia,and ovarian cancer.It is recommended that comprehensive prevention and control strategies should be improved for overweight and obesity and targeted interventions should be implemented for high-risk cancers and specific populations to reduce the burden of related cancer diseases.