The invention discloses a school uniform with an adjustment function. The school uniform comprises a main school uniform body; two garment sleeves are symmetrically meshed with the two sides of the main school uniform body through annular zippers, a water seal zipper is arranged in the middle section of the front surface of the main school uniform body, the outer side of the water seal zipper is provided with hook and loop fastener assemblies, two extension cloth sections are sewn at the two sides of the main school uniform body, the two ends of the external portion of each extension cloth section is provided with a strip-shaped zipper, close-fitting belt penetrating holes are formed in the main school uniform body, and a uniform-body close-fitting belt penetrates through the interior of the close-fitting belt penetrating holes. According to the school uniform with the adjustment function, the close-fitting belt penetrating holes can be contracted through the uniform-body close-fittingbelt, the main school uniform body is waisted according to the actual waist size, the wearing shape is more attractive, and meanwhile the size of the main school uniform body is conveniently adjusted; the two extension cloth sections are sewn at the two sides of the main school uniform body, the strip-shaped zippers are arranged at the two ends of the external portions of the extension cloth sections, and the size of the main school uniform body is conveniently changed.