目的 分析广州市6 ~ 70岁研究人群的肌肉质量（skeletal muscle mass， SMM）增龄性变化特征，并探讨不同体质量状态人群的肌肉发展模式。 方法 采用横断面调查，纳入3 316名6 ~ 70岁广州市居民。使用双能X线吸收法测量SMM，计算身高校正的全身肌肉质量指数（skeletal muscle mass index， SMMI）和四肢骨骼肌质量指数（appendicular skeletal muscle mass index，ASMMI）。采用LMS法拟合性别年龄别肌肉指标百分位数曲线，并按体质量状态进行分层分析。 结果 男性各年龄段SMM均高于女性。男、女性SMMI在6 ~ 12岁期间均快速增长，年均增长率分别为4.6%和3.9%。男性SMMI在12岁后增速减缓，13 ~ 19岁年均增长1.9%，20岁后进入缓慢增长阶段，43岁达峰值；女性SMMI在13 ~ 19岁年均增长0.8%，47岁达峰值，55岁后SMM下降加速。各性别ASMMI随年龄变化特征与SMMI相似，但ASMMI峰值年龄更早。根据体质量状态分层，肥胖者SMMI峰值最高，但峰值年龄之后下降速度最快；消瘦者SMM峰值最低但下降较缓。 结论 研究人群的SMM发展存在性别和年龄特异性，并且中老年期SMM衰减存在部位差异，四肢肌肉衰减出现最早。肥胖人群呈现“高峰值－快下降”模式。由于研究为非随机抽样，结果外推性受限，但研究结果可为促进肌肉健康提供初步参考依据。

Objective To analyze the age-related changes in muscle mass within the study population aged 6 to 70 years in Guangzhou， and to explore the muscle development patterns among individuals with different weight statuses. Methods A cross-sectional study was carried out， encompassing 3，316 residents aged 6–70 years in Guangzhou. Dual-energy X-ray absorptiometry was employed to measure muscle mass. Subsequently， the skeletal muscle mass index （SMMI） and appendicular skeletal muscle mass index （ASMMI） were computed after adjusting for body height. The LMS method was utilized to fit the sex-and age-specific percentile curves of muscle indices， and a stratified analysis was performed according to body weight status. Results Muscle mass in males was greater than that in females across all age groups. Both genders showed rapid SMMI growth between the ages of 6 and 12 years， with average annual growth rates of 4.6% for males and 3.9% for females. For males， the growth rate of SMMI slowed down after the age of 12 years， with an average annual growth of 1.9% from 13 to 19 years， and then entered a slow-growth phase after the age of 20 years， reaching its peak at the age of 43 years. For females， SMMI increased by an average of 0.8% per year from 13 to 19 years， reached its peak at the age of 47 years， and further decreased after the age of 55 years. The age-related changes in ASMMI were similar to those of SMMI， although the peak ASMMI occurred at an earlier age. When stratified by body weight status， individuals with obesity had the highest peak SMMI but the most rapid decline after the peak age. In contrast， underweight individuals had the lowest muscle mass peak but a much slower decline trend. Conclusions Results indicate a distinct age- and sex-specific pattern of muscle mass development within the study population. The decline of muscle mass during middle and old age exhibits site-specific characteristics， with appendicular skeletal muscle experiencing the earliest decline. The changes in muscle mass among obese individuals follow a pattern of “high peak value – rapid decline”. Owing to the non-random sampling design， the generalizability of the findings is restricted. Nevertheless， the findings can offer preliminary evidence for promoting muscle health.