No-tillage is an important agricultural measure that is conducive to improving soil carbon sequestration capability and mitigating climate change. However, the responses of soil organic carbon content and greenhouse gas emissions (CO2, CH4, N2O) to no-tillage and their influencing factors in farmland in China are still unclear due to the differences in hydrothermal conditions, soil characteristics, and agricultural management practices in different regions of China. Therefore, 574 experimental results from 179 related field trials in China were sorted out by using the Meta-analysis method in this study. Two comparative models, that is no-tillage with straw removal (NT0) versus conventional tillage with straw removal (CT0), and no-tillage with straw incorporation (NTS) versus conventional tillage with straw incorporation (CTS) were set up to systematically assess the effects of no-tillage on organic carbon content in the soil in the top layer of farmland (0-20 cm) and CO2, CH4, and N2O emissions in different climatic zones in China. The results showed that compared with traditional tillage, no-tillage increased soil organic carbon content by 4.08% (P < 0.001), and reduced CO2 and CH4 emissions by 8.61% (P < 0.001) and 19.75% (P < 0.001), respectively, but did not have a significant effect on N2O emissions. Analyzed by climatic zones, no-tillage had the best effect on the enhancement of soil organic carbon in the mid-temperate zone with an increase of 4.19% due to the improvement of hydrothermal conditions, which was also conducive to the enhancement of soil surface nutrients as well as the enhancement of the water retention capacity. In the mid-temperate zone and the warm-temperate zone, the CO2 emission under no-tillage was significantly reduced by 5.45% and 17.3%, respectively, and the N2O emission was significantly reduced by 9.7% and 22.97%, respectively. However, in subtropical regions, due to the accelerated decomposition of organic carbon in soil, the inhibitory effect of no-tillage on CO2 emissions was weakened. The intensification of the denitrification process even led to an increase in soil N2O emissions. Rice fields are the main source of CH4 emissions in China. The implementation of no-tillage reduced the CH4 emissions of rice fields by 21.7% in subtropical regions. However, there was a significant negative correlation between the effect values of CH4 and N2O. The emission reduction effect of no-tillage on N2O could be enhanced by increasing soil pH and prolonging the duration of no-tillage. In addition, crop rotation increased the soil organic carbon content while reducing the emissions of the three greenhouse gases. The results of this study can provide a scientific basis for the targeted guidance of no-tillage technology application and the mitigation of climate change in China.