Objective To explore the characteristics of short-term static balance of obese children by comparing the excursion of center of pressure (COP) in obese and non-obese children under six kinds of standing circumstances. Methods By using the Footscan balance plate system, parameters of COP excursion for 47 obese children and 50 non-obese children standing on both feet or single foot with eyes open or eyes closed for 10 seconds were obtained, respectively. Results The maximum COP displacement in anterior-posterior direction of obese children was significantly greater than that of non-obese children during standing on both feet with eyes closed. During standing on left foot with eyes open, the sway velocity of obese boys was significantly lower than that of non-obese boys; the maximum COP displacement in medial-lateral direction of obese boys was significantly lower than that of non-obese boys and the maximum displacement of COP in medial-lateral direction of obese girls was significantly greater than that of non-obese girls. The sway velocity of boys was significantly greater than that of girls during standing on left foot with eyes closed. Conclusions In short period of time, the static balance of obese children in anterior-posterior direction was worse than that of non-obese children during standing on both feet with eyes closed. Obesity had different impacts on static balance of different genders. The performance of static balance for obese boys was better than that of non-obese boys, while the performance of static balance for obese girls was worse than that of non-obese girls during standing on left foot with eyes open. Girls had a better static balance performance than boys during standing on left foot with eyes closed. There were no significant differences in static balance performance between boys and girls under the other circumstances. As static balance of children is affected by obesity and gender, it is suggested that different methods of losing weight should be considered for obese children of different genders.