目的 分析1990—2021年我国儿童下呼吸道感染（lower respiratory infection, LRI）发病和死亡的变化趋势与未来预测，并比较不同年龄段儿童的病原学特征。 方法 基于全球疾病负担数据库，收集1990—2021年中国儿童LRI的流行病学数据，对比分析我国、全球以及高社会人口指数（socio-demographic index, SDI）地区儿童LRI的流行趋势及未来预测，并探讨不同病原体对我国儿童LRI的影响等。 结果 1990—2021年，我国儿童LRI疾病负担低于全球平均水平，但仍高于高SDI地区。我国儿童LRI发病率和死亡率呈显著下降趋势，其中5岁以下儿童的降幅最明显，而10~14岁LRI发病率降幅低于全球水平。预测显示，2022—2040年我国儿童LRI发病率和死亡率将持续下降。细菌仍是我国儿童LRI的最主要病原体。不同年龄组的病原谱构成存在显著差异，5岁以下儿童的病毒性LRI疾病负担高于5~14岁儿童，而非典型病原体的疾病负担则低于5~14岁儿童。 结论 1990—2021年我国儿童LRI负担总体呈下降趋势，且预计未来将持续下降。10~14岁儿童LRI发病率的降幅落后于全球水平，提示该年龄群体在防控中尚存在薄弱环节。儿童各年龄段的致病谱构成不同，建议针对不同年龄群体实施精准化的干预策略，并持续进行病原谱的动态监测。

Objective To analyze trends and future projections of lower respiratory infection (LRI) incidence and mortality among children in China from 1990 to 2021, and to compare etiological characteristics across age groups. Methods Epidemiological data for pediatric LRI in China from 1990 to 2021 were obtained from the Global Burden of Disease database. Comparative analyses examined trends and projections for China, the global population, and high socio-demographic index (SDI) regions. The influence of different pathogens on pediatric LRI in China was also assessed. Results From 1990 to 2021, the burden of LRI among children in China was lower than the global average but higher than that in high-SDI regions. Incidence and mortality rates showed a significant downward trend, with the most pronounced decline in children under 5 years of age, while the decline in LRI incidence among those aged 10-14 years was slower than the global level for the same age group. Projections for 2022-2040 indicated continued decreases in incidence and mortality of pediatric LRI in China. Bacterial infections remained the predominant cause of pediatric LRI in China. Marked age-specific differences in pathogen spectra were observed: viral LRI burden was higher in children under 5 years than in those aged 5-14 years, whereas the burden due to atypical pathogens was lower in children under 5 years than in those aged 5-14 years. Conclusions From 1990 to 2021, the overall burden of pediatric LRI in China shows a declining trend and is predicted to continue to decrease. The slower decline in LRI incidence among children aged 10-14 years compared with the global level indicates a weakness in prevention for this age group. Distinct age-specific pathogen profiles suggest the need for age-targeted interventions and continuous surveillance of pathogen spectra.