Objective To assess the motor function of school-aged children with congenital muscular torticollis (CMT), and analyze the spatiotemporal parameters of their walking motion as well as the kinematic parameters of the trunk and lower limbs, so as to explore the potential long-term impact of CMT on the growth and development of children. Methods Using three-dimensional (3D) gait analysis technology, the gait of children with CMT was evaluated in detail and compared with that of normal children. The motion angles and ranges of the trunk, pelvis, hip, knee, and ankle joints, along with spatio-temporal parameters, were analyzed. Thirty-one children with CMT aged 6–12 years were recruited into the torticollis group, and 31 normal children of the same age range were included in the control group. The data of the torticollis group were divided into the healthy side and the affected side based on the side of the torticollis. Statistical analysis was performed among the three groups to calculate the differences in kinematic and spatio-temporal parameters. Results Compared with nomal children of the same age in the control group, significant differences were observed in the affected and unaffected sides of the torticollis group in terms of stride length, gait speed, percentage of support phase time, average ankle inversion angle during the swing phase, average ankle inversion angle during the support phase, average foot orientation angle during the support phase, average ankle internal rotation angle relative to the tibia during the stance phase, average knee valgus angle during the stance phase, average shoulder joint elevation, and shoulder joint height at landing. Specifically, the torticollis group had significantly lower stride length, gait speed, ankle inversion angle, knee valgus angle, and foot eversion angle in both the affected and unaffected sides compared to the control group, while the percentage of support phase time and the internal rotation angle of the foot relative to the tibia during the stance phase were higher than those in the control group. Conclusions For school-aged children with CMT, there are still residual manifestations of overall motor development abnormalities. These abnormalities also affect the non-affected side. Children with CMT have a relatively high risk of developing uneven shoulders, their overall walking efficiency is lower than that of normal children of the same age, and they exhibit lower limb motor abnormalities such as insufficient ankle joint stability.