In this study, we analyzed sarcopenia prevalence and the cut-off points for skeletal muscle mass index (SMI), gait speed, and handgrip strength in young (18-39 years), middle-aged (40-59 years), and elderly (>60 years) individuals (n=1685) from Zhejiang Province in China. The prevalence of sarcopenia among individuals above 65 years was 2.21%, 4.87%, 5.31%, 14.16%, and 16.37% according to five diagnostic criteria (AWGS2019, AWGS2014, EWGSOP1, EWGSOP2, and local standard). The mean SMI (Kg/m2) was 7.961±0.7966, 7.801±0.7276, and 7.544±0.7493, respectively, in young, middle-aged, and elderly males. The mean SMI in young, middle-aged, and elderly females was 6.1570±0.5658, 6.604±0.5658, and 6.248±0.7483, respectively. SMI correlated negatively with age (r=-0.2344, P<0.001), but was not associated with age in females (r=0.0573, P=0.1463). The cut-off point of SMI for sarcopenia was ≤6.3678 kg/m2 in males and ≤5.0254 kg/m2 in females. These findings shows that the prevalence of sarcopenia increased gradually with age and varied significantly based on the diagnostic criteria used for this analysis. The mean SMI of young women was lower than in middle-aged women, making them an unsuitable reference population for determining cut-off values for sarcopenia diagnosis.