Concurrent changes in patterns of precipitation and increases in nitrogen (N) deposition can significantly affect ecosystem carbon (C) cycling by altering plant- and microbe-mediated soil C processes. However, how interactions between altered precipitation and N deposition regimes influence soil respiration (SR) in salinealkaline desert steppes remains unclear, particularly when precipitation is highly variable. This study investigates changes in SR based on a three-year field experiment, which examined the combined effects of two global change factors (five precipitation levels and two N addition levels) in a saline-alkaline desert steppe in northwest China. SR rates exhibited a single peak in 2019, a wet year, but did not exhibit any obvious trends in the dry years of 2020 or 2021. Decreased precipitation during the growing season had little influence on SR, particularly during dry years. Increased precipitation simulated SR during the experimental period. However, extreme increases in precipitation weakened this effect in most cases. Neither plant characteristics (biomass, diversity, and C:N:P stoichiometry) nor microbial traits (biomass C:N:P stoichiometry) explained variation in SR. Further analysis revealed that altered precipitation stimulated SR by regulating soil water availability, alleviating plant N limitation, and promoting plant biomass accumulation. In contrast, N addition and its interactions with altered precipitation did not have a significant effect (P > 0.05). This study highlights the role of precipitation change in driving soil C dynamics in saline-alkaline desert steppes and its dominant influence compared to N deposition. These findings provide empirical evidence for understanding how altered precipitation and enhanced N deposition affect grassland C emissions under variable soil pH and for improving the accuracy of projections of dryland C sink potential under global change.