ObjectiveThis study intends to analyze the changing disease burden of mood disorders in China from 1990 to 2021 and project the epidemiological trends in the next two decades. MethodsThis study uses data from the Global Burden of Disease (GBD) 2021 database on three mood disorders in China (bipolar disorder, major depressive disorder, and dysthymia) from 1990 to 2021. The indicators such as age-standardized number of diseases and disability-adjusted life years (DALYs) were used to explore the characteristics of time, gender, and age distribution of the disease burden of mental disorders. The BAPC model was used to predict the disease burden in the next two decades. ResultsIn 2021, the number of cases of dysthymia, MDD, and BD in China was 27.84 million, 26.0 million, and 2.85 million, with an increase of 73.24%, 38.33%, and 36.79% compared with 1990, respectively. In 2021, DALYs of dysthymic disorder, MDD and BD were 2.67 million, 5.2 million and 0.61 million person-years, which increased by 71.45%, 34.29% and 34.76% compared with 1990, respectively. The burden of mood disorders is heavier among women and the middle-aged and elderly population. In addition, it is expected that ASPR and ASDR of dysthymia will continue to increase after a brief decline, MDD will show a downward trend, while BD will show a slight upward trend in the next two decades. ConclusionThe disease burden of mood disorders in China remains substantial, with dysthymia and BD showing persistent upward tendency. More resources should be invested in mental health care.