<p>To investigate the effects of the LEG structured curriculum model on the physical fitness of preschool children aged 3 to 6 years.A cluster random sampling method was employed to select a total of 221 preschool children as research subjects, comprising both experimental and control groups.The Chinese National Physical Fitness Standards (Preschool Section) were used to assess the physical fitness development levels of preschool children aged 3 to 6 years.The experimental results were statistically analyzed using independent samples t-tests and paired samples t-tests.After a 12-week experimental intervention, we found that: 1) The level of physical fitness development in young children showed an upward trend with increasing age.2) Both experimental and conventional curricula positively influence the physical development of children aged 3 to 6, but experimental curricula yield superior results compared to conventional ones.3) Gender differences exist in the physical fitness development of young children. Boys and girls in the experimental group showed greater improvements in physical fitness scores compared to the control group, without introducing new gender differences. Meanwhile, children in the control group exhibited more diverse gender differences than those in the experimental group.A 12-week intervention demonstrated that the LEG structured curriculum model significantly enhances physical fitness development in children aged 3 to 6 years without inducing new gender disparities. It is recommended that this course model be incorporated into the kindergarten outdoor activity curriculum system and promoted. Meanwhile, in the design and implementation of structured physical education programs, attention should not be limited to children’s age and gender differences, greater emphasis should be placed on the intrinsic connections and positive transfer between their fundamental motor skills, and systematically promote the development of children’s physical fitness.</p>