Abstract: Clarifying the impacts of different winter cropping patterns on the variations of soil organic carbon (SOC) fractions and rice grain yields can provide a theoretical basis for the green and sustainable production of agriculture in rice-growing areas of China. In this study, the effects of different winter planting patterns winter fallow as control (CK), winter planting of rape (Ra), winter planting of Chinese milk vetch (Mv) and winter planting of hairy vetch (Hv) on SOC, total labile organic carbon (TLOC), high labile organic carbon (HLOC), medium labile organic carbon (MLOC), low labile organic carbon (LLOC), recalcitrant organic carbon (ROC), carbon pool management index (CPMI), and rice grain yields were studied quantitatively in the Hanzhong Basin in southern Shaanxi Province. The results showed that the average annual rice grain yield under Hv was significantly increased by 6.6% compared with the CK, but there was no significant difference among Hv, Mv and Ra. Compared with the CK, the Hv and Mv significantly increased SOC content by 12.4% and 8.4%, and increased TLOC content by 19.6% and 13.7%, respectively. However, there was no significant difference in SOC and TLOC content between Ra and CK. Compared with the CK, the Ra, Mv, and Hv significantly enhanced HLOC content by 12.5%, 26.1%, and 37.0%, respectively. In addition, the MLOC contents under Mv and Hv were also significantly increased by 10.0% and 14.4%, respectively, relative to the CK. Meanwhile, the CPMI under Mv and Hv increased significantly by 14.8% and 29.4%, respectively, relative to the CK. What’s more, the CPMI under Hv was also 19.4% higher than that under Ra. Therefore, in the paddy fields of the Hanzhong Basin in Shaanxi Province, winter planting of green manure, especially winter planting of hairy vetch, can simultaneously achieve increased rice grain yield and enhanced soil carbon sequestration, which is conducive to the green and sustainable utilization of paddy fields in this region and the realization of China’s carbon neutrality goal.