Bone mass is a key determinant of osteoporosis and fragility fractures.Epidemiologic studies have shown that a 10％ increase in peak bone mass (PBM) at the population level reduces the risk of fracture later in life by 50％.Low PBM is possibly due to the bone loss caused by various conditions or processes that occur during adolescence and young adulthood.Race,gender,and family history (genetics) are responsible for the majority of PBM,but other factors,such as physical activity,calcium and vitamin D intake,weight,smoking and alcohol consumption,socioeconomic status,age at menarche,and other secondary causes (diseases and medications),play important roles in PBM gain during childhood and adolescence.Hence,the optimization of lifestyle factors that affect PBM and bone strength is an important strategy to maximize PBM among adolescents and young people,and thus to reduce the low bone mass or osteoporosis risk in later life.This review aims to summarize the available evidence for the common but important factors that influence bone mass gain during growth and development and discuss the advances of developing high PBM.