ObjectiveTo analyze temporal trends in the burden of endometriosis in China and globally from 1990 to 2021, and to project trends from 2022 to 2040. MethodsData on incidence, prevalence and disability-adjusted life years (DALYs) of endometriosis in China and worldwide from 1990 to 2021 were extracted from the Global Burden of Disease 2021 (GBD 2021) database. Joinpoint regression was used to estimate annual percentage changes. Autoregressive integrated moving average (ARIMA) models were constructed to forecast disease burden from 2022 to 2040, and Bayesian age-period-cohort (BAPC) models were applied for validation. ResultsFrom 1990 to 2021, the burden of endometriosis decreased both in China and globally, with a greater overall decline in China; however, age-standardized incidence and prevalence in China remained consistently higher than the global average. In China, the age pattern of onset showed a multimodal distribution, with peak ages occurring approximately 5-10 years later than those worldwide. ARIMA and BAPC projections suggested that from 2022 to 2040 all burden indicators in China will continue to decline steadily, while global indicators will also decrease but with smaller reductions and greater uncertainty. ConclusionThe marked reduction in endometriosis burden in China reflects advances in medical care and supportive public health policies. Strengthening early screening and intervention during adolescence and the perimenopausal period is essential to further reduce the disease burden. Globally, more equitable allocation of medical resources and coordinated policy actions are needed to address the long-term challenges posed by endometriosis.