Objective: The finite element method was developed in Chinese women holding children. Up to 66.47% of the 55-65 years old Chinese women stayed home and acted as grandchildren sitter (e.g. lifting kid in daily life). In consequence of these frequently loading-bear, the chronic lumbar fatigue probably caused higher risk of lumbar degeneration and fatigue. In this study, A lumbar finite element model (FEM) with specific bone mineral density(BMD) and geometry of Chinese 55-65 years old women were developed and validated to predict the bio-mechanical response. Method The material properties of elder women lumbar vertebra was modified according to degenerated bone mineral density, and geometry was adjusted based on 55-65 years old women’s intervertebral disc height. The motion of lifting kid in 3 different loading condition were simulated by the elder women FEM, and the stress and strain distribution were calculated and predicted, then the limitations of fatigue tolerances of the lumbar spine were also predicted. Result The calculated maximum intradiscal pressure were located in L5-S, which were 3.56 Mpa, 5.38 Mpa and 1.47 Mpa, while the maximum effective stress contribution of endplate cartilage were located in posterior edge of L5 up and down endplate cartilage, which were 16.55 Mpa, 23.58 Mpa and 26.55 Mpa in the bending without lifting weight, the bending with lifting 3-year-old child and upright with 3-year-old child posture respectively. More importantly, the fatigue risk limitation frequency(18 times) of upright with 3-year-old dummy was predicted with the functional equation of fatigue and stress which deduced by genetic algorithm, which combined with the effective stress of lumbar vertebrae spongy bone calculated from FEM. Conclusion These results imply that the lifting child motion could increase the risk of lumbar fatigue and degeneration in elder women, and the elder women should keep below the limitation frequency of the motion of lifting kids in the daily life. With the deterioration of aging problem in China and the increasing of newborns, this study could put forward a scientific guidance to 55-65 years old women who lifting kid in daily life frequently.