Objective To investigate the gait characteristics of school-age children with generalised joint hypermobility (GJH). Methods The kinematic and kinetic data of lower extremity joints in 56 children with GJH and 56 healthy children were collected by 3D motion capture system and 3D force plates, and the differences between the two groups were compared and analyzed. Results (1)Kinematics: The mean ankle inversion angle, maximum hip adduction angle, mean foot progression angle in stance phase and maximum foot clearance angle decreased in the GJH children group, while the maximum foot internal rotation angle and the knee flexion Angle in the middle stance phase increased. (2)Kinetics: The maximum power of knee and hip joints and the maximum inversion moment of ankle joints during stance phase were reduced in GJH children. (3)Temporal and Spatial Parameters: step length, walking velocity and cadence decreased in GJH children group, while stance phase percentage and step width increased. Conclusion The walking efficiency and balance stability of children with GJH are decreased. The line alignment is abnormal in ankle joint. And knee joint function needs long-term attention.