This study investigated the spatial-temporal gait patterns and motor strategy in children with and without Down syndrome (DS) when walking from the level ground to the stairs. Six children with DS and eleven typically developing (TD) children aged 5-11 years from the greater Atlanta participated in this study. A full body 35 marker set and a Vicon motion capture system were used for data collection. Three three-step wooden staircases with the riser height of 17 cm (LS), 24 cm (MS), and 31 cm (HS) were randomly presented to the subjects. We examined anticipatory locomotor adjustments in spatial-temporal gait parameters (i.e. step width, step length, step time, step velocity, stance time) while the subject approached a staircase. While going up the stairs, we examined the aforementioned gait parameters and included other variables such as vertical toe clearance and horizontal toe velocity above the edge of stairs. In addition, we categorized motor strategies that were adopted to negotiate a staircase. A series of mixed ANOVA with repeated measures were conducted on each spatial-temporal gait parameter. Our results demonstrated that children with DS displayed some anticipatory locomotor adjustments while approaching a staircase, but the pattern was different from those in TD children. Specifically, while approaching a staircase, TD children maintained a similar step length and velocity but decreased step width, whereas children with DS decreased step length and velocity but maintained step width. While going up a staircase, children with DS chose a crawling strategy more often, and displayed a wider step width and a lower horizontal toe velocity than TD children. Further, children with DS produced a higher toe clearance (“overshooting”) from the leading limb than TD children under the LS condition and a lower toe clearance (“undershooting”) under the HS condition. Our results suggest that children with DS aged 5-11 years are able to display some anticipatory locomotor adjustments while negotiating a staircase, but still developmentally behind TD children. These findings allow us to understand motor function and the environmentally related locomotion adaptations in children with DS.