The components and contents of high-molecular-weight glutenin subunits(HMW-GS) in wheat grains affect glutenin macropolymer(GMP) size, which is considered an important flour quality trait in wheat. Four wheat cultivars(Shiluan 02-1, Yannong 24, Jinan 17 and Lumai 21) with different end-use qualities were used to investigate the HMW-GS and GMP contents, and the GMP particle distributions in grain produced under irrigated and rainfed conditions. The percent volume of GMP particles and the contents of HMW-GS and GMP were affected by genotype and soil water. Genotype × soil water interaction was significant only for GMP particles <12 μm and >100 μm in the growing season of 2010–2011. Irrigated and rainfed conditions had different influences on the GMP particle distribution in the four cultivars. Compared to irrigated treatment, the rainfed treatment had higher accumulations of HMW-GS and GMP, especially in cultivars Yannong 24, Jinan 17 and Lumai 21. Rainfed conditions also increased the proportion of large size particles of GMP, indicating that different water regimes had an effect on grain quality. According to correlation coefficients(r), the contents of HMW-GS and GMP in grains were negatively correlated with the volume of <12 μm GMP particles, but positively correlated with GMP particles >100 μm. The components and contents of high-molecular-weight glutenin subunits (HMW-GS) in wheat grains affect glutenin macropolymer (GMP) size, which is considered an important flour quality trait in wheat. Four wheat cultivars (Shiluan 02-1, Yannong 24 , Jinan 17 and Lumai 21) with different end-use qualities were used to investigate the HMW-GS and GMP contents, and the GMP particle distributions in grain produced under irrigated and rainfed conditions. The percent volume of GMP particles and the contents of HMW -GS and GMP were affected by genotype and soil water. Genotype × soil water interaction was significant only for GMP particles <12 μm and> 100 μm in the growing season of 2010-2011. Irrigated and rainfed conditions had different influences on the GMP particle Compared to cultivars Yannong 24, Jinan 17 and Lumai 21. Rainfed conditions also increased the proportion of large size particles of GMP, indicating that different water regimes had an effect on grain quality. According to correlation coefficients (r), the contents of HMW-GS and GMP were negatively correlated with the volume of <12 μm GMP particles, but positively correlated with GMP particles> 100 μm.