Objective: To explore the association of body fat mass and distribution indices including fat mass percentage (FMP), visceral fat area (VFA) and percentage of trunk fat mass (%TFM) with blood pressure in children to inform early management of blood pressure in children. Methods: Based on the Beijing Child Growth and Health Cohort in Shunyi District, lifestyle questionnaire survey, baseline and follow up physical examination were conducted among children from October to November 2018 and September 2020. Bioelectrical impedance analysis (BIA) was used to measure the body composition, and 1 098 participants with completed data were finally included. Results: Both body fat indices and blood pressure increased with age in boys and girls. For FMP, VFA, and %TFM, no significant differences presented between sex at baseline, while FMP, VFA, and %TFM were significantly higher in boys than girls at follow up ( t=2.73, 3.76, 3.41, P <0.01). Before and after adjusting for age, height and lifestyles or not, linear mixed effect models showed longitudinal associations existing between body fat indices and blood pressure in both boys and girls ( β=0.64-3.48, P <0.05). The association coefficients of body fat indices with systolic blood pressure were ranked as %TFM>FMP>VFA in both boys and girls. The association coefficients of body fat indices with diastolic blood pressure were ranked sequentially as FMP>%TFM>VFA in boys, and VFA>FMP>%TFM in girls. Conclusion Longitudinal associations are observed between body fat indices and blood pressure in children. Primordial prevention of high pressure should pay attention on body fat distribution.