Objective: To explore the correlation between gross motor development and physical activity level of preschool children at different altitudes, so as to provide exercise basis for the development of gross motor ability. Methods: A total of 188 preschool children living in the 3 240 m high plateau (Hi group) in Tashkurgan County, 175 children living in the 1 290 m low plateau (SubHi group) in Kashgar District and 191 children living in the 450 m high plateau (Pla group) in Gaochang District of Turpan were selected as subjects. The children were assessed for gross motor development and tested for physical activity. Results: With the increase of age, the scores of MPA, VPA, MVPA and gross movement of preschoolers in each test group showed an upward trend. The above indexes in SubHi group were significantly higher than those in Hi group at 5 years old, and those in Pla group at 5 years old were significantly higher than those in Hi group ( P <0.05). The level of MPA in SubHi group and Pla group was significantly higher than that in Hi group at 4 years old, and the MVPA in SubHi group at 5 years old was significantly higher than that in Hi group ( P <0.05). SubHi group and Pla group were significantly higher than Hi group at 5 years of age, and Pla group was significantly higher than SubHi group at 4 years of age ( P <0.05). There were no significant differences in the related indexes of gross motor among girls at different altitude groups ( P >0.05). The LPA of the Hi group and the SubHi group was positively correlated with the operational movement score ( r =0.60,0.44), and the LPA of the Pla group was positively correlated with the displacement movement score ( r =0.69).There was a positive correlation between MPA and displacement score of Hi group ( r =0.53), displacement score and gross movement total score of SubHi group ( r =0.45,0.59), and gross movement scores of Pla group ( r =0.69, 0.52 , 0.73). Except the displacement score and gross movement total score of the Pla group, VPA was positively correlated with the gross movement scores of each group ( P <0.05). Conclusion There is a certain correlation between gross motor development and physical activity level in children aged 3-6 years.MVPA can be used as an effective means to improve the development of rough movements of 3-6 year old children.