The soil carbon cycling in terrestrial ecosystems on the Loess Plateau of China is particularly sensitive to the altered drying and rewetting (DRW) events exacerbated by prolonged drought due to global climate change. However, how microbes mediate carbon release under increased drought durations in the DRW treatment remains unclear. An indoor experiment was conducted by adjusting the length of dry period in soil samples from the Loess Plateau, including 5-day drying at 5% water holding capacity (WHC) followed by 15-day rewetting at 60% WHC (D5W15), D10W10 and D15W5 in 4 cycles respectively with those under conditions of constant 5% WHC (D20) and 60% WHC (W20) as control. Compared to W20, treatments under the D5W15, D10W10 and D15W5 reduced carbon dioxide (CO2) emission by 52.63, 57.10 and 64.66 mu g CO2-C g-1 soil carbon, respectively. Longer drought durations promoted the sharp enhancement of soil carbon mineralization triggered by rewetting in DRW and this facilitating effect became weaker with the increased number of cycles. Correspondingly, the increased drought duration and number of cycles of DRW treatments resulted in the reduction of bacterial diversity and richness, with the effect on bacteria more significant than fungi, and promoted the interaction of microorganisms shown by the more complex co-occurrence network. The microbial biomass under DRW treatment was slightly lower than that under control. DRW cycles under different drought durations reduced carbon loss about 58.13 mu g CO2-C g(-)(1) soil, with bacterial diversity and microbial biomass emerging as the primary drivers for this reduction.