Abstract: OBJECTIVE：The aims of this paper were to analyze the incidence and mortality trends of colorectal cancer in China from 1990 to 2021，to explore the impact of age，period and cohort effects，to predict the future trend of colorectal cancer from 2022 to 2045， and to provide data support for control strategies and resource allocation. METHODS： Based on the Global Burden of Disease (GBD) database， Joinpoint regression analysis was used to evaluate the trend of changes in different time periods. The age-period-cohort model was used to analyze the age effect，period effect and cohort effect of the incidence and mortality of colorectal cancer in China from 1992 to 2021. Through Nordpred prediction model，combined with gender differences， the standardized morbidity and mortality of colorectal cancer in 2022—2045 were predicted. RESULTS：From 1990 to 2021，the standardized incidence of colorectal cancer in China continued to rise，with an average annual percentage change (APC) of 1.64% [95%CI (1.38%，1.89%)，P<0.01]. The increase was particularly significant in men. The standardized mortality rate showed an overall downward trend， with an APC of -0.41% [95%CI (-0.58%，-0.24%)，P<0.01]，but rebounded between 2014 and 2021. The incidence and mortality of colorectal cancer were affected by the complex interweaving of age， period and cohort effects. The age effect shows that the elderly group was a high-risk group. The period effect and cohort effect show that the risk of disease decreased year by year，while the risk of death increased. The gender difference was significant，and the morbidity and mortality of males were higher than those of females. The prediction results show that the standardized incidence of colorectal cancer in China will continue to rise in the future. CONCLUSION： From 1990 to 2021， the incidence of colorectal cancer in China showed a continuous increase，whereas the mortality rate declined overall but rebounded in recent years. Age，period， and cohort effects significantly contributed to the disease burden， with older adults and males as high-risk populations. Projections suggest that the incidence of colorectal cancer will continue to rise in the coming decades，indicating a persistent public health challenge. Strengthening early screening，timely diagnosis，and standardized treatment， along with optimizing resource allocation， particularly for male and elderly high-risk groups，will be essential to reduce the future burden of colorectal cancer.

Key words: colorectal cancer, incidence rate, mortality, age-period-cohort