This dataset provides high-resolution triaxial accelerometry data and synchronized energy expenditure (EE) measurements for Chinese primary and secondary school students. The study involved a stratified sample across 12 grades (Grades 1-12). Key features include: Multiple Sensor Placements: Data were collected from 9 body locations, including the chest, left/right wrists, left/right hips, left/right thighs, and left/right feet. Diverse Activity Protocols: Participants performed 13 types of activities: Radio Calisthenics, Vigorous Running, Brisk Walking, Basketball Dribbling, Jogging, Slow Walking, Rope Skipping, Basketball Shooting, Single-leg Hopping (Left/Right), Badminton, Soccer Passing, and Soccer Dribbling. Gold Standard Reference: Energy expenditure is provided as Metabolic Equivalents (METs), including raw data and 10-second windowed averages. This dataset is designed to support researchers in developing robust human activity recognition (HAR) algorithms and precise energy expenditure estimation models tailored for the pediatric population.