Background <p>Colon and rectum cancer (CRC) is an increasing public health concern in China due to rising incidence and disability, particularly among aging populations. Despite medical advancements, low physical activity remains a major modifiable risk factor. This study evaluates CRC burden trends from 1990 to 2021, focusing on demographic and temporal effects.</p> Methods <p>Using age-standardized rates for mortality, disability-adjusted life years (DALYs), years lived with disability (YLDs), and years of life lost (YLLs), this retrospective analysis employed Joinpoint regression, decomposition, and age-period-cohort modeling to explore temporal changes and demographic drivers of CRC outcomes. Data were segmented by gender and age groups to assess trends and contributing factors.</p> Results <p>CRC mortality and DALYs have demonstrated divergent trends over the past three decades. While mortality rates initially declined, recent years have shown an uptick, particularly among males. In contrast, YLD rates have risen consistently, reflecting an increasing burden of non-fatal outcomes, especially in older adults. Age-period-cohort analysis revealed reduced mortality and DALY rates in recent cohorts and periods, highlighting the impact of improved healthcare and public health interventions. However, decomposition analysis identified aging as the most significant driver of the increasing burden, with population growth and epidemiological changes also contributing. Notably, younger cohorts (25–45 years) in recent periods exhibited a rising burden of DALYs, indicating emerging public health challenges.</p> Conclusions <p>The burden of CRC attributable to low physical activity in China reflects a complex interplay of demographic and epidemiological factors. Addressing this burden requires targeted public health strategies that promote physical activity, mitigate disability, and prioritize interventions for vulnerable groups, particularly the elderly and younger at-risk cohorts.</p>