The impacts of drought stress on crop yield and quality are substantial. Drought priming during the early growth stage of plants has been shown to improve tolerance to drought stress during the reproductive stage, although its effects on grain quality remain elusive. This study investigated the influence of drought priming on starch and protein levels in grains under drought stress during grain filling. Our results revealed that drought stress leads to a reduction in the contents of starch and its constituents, while simultaneously increasing glutenin macropolymers and protein fractions. Notably, drought primed plants under drought stress (PD) exhibited mitigated declines in the contents of starch and its components, leading to improvements in starch swelling power and pasting properties. In addition, PD resulted in a slight increase in the protein fractions, limiting the overall rise in total protein content compared to drought stress alone. The results of our study underscore the efficacy of drought priming as a strategy to counteract the negative effects of drought stress on grain quality, particularly by minimizing starch losses and restraining protein content elevation.