Soil respiration (Rs) is a main process of carbon release from soil to the atmosphere. As the southern margin of the Eurasian permafrost zone, the Great Xing’an Mountains host the most extensive and intact permafrost in Northeast China, and are critical for understanding terrestrial carbon cycling, yet year-round Rs observations remain scarce. Here we used multi-year, high-frequency chamber measurements to quantify the temperature sensitivity (Q₁₀) of Rs and soil carbon emissions across four distinct freeze-thaw stages in the core permafrost region of the Great Xing’an Mountains. Rs exhibited the strongest Q₁₀ in the spring thawing stage (10.77) and the autumn freezing stage (7.37), and the Q₁₀ in the complete thawing (2.67) and freezing (2.45) stages declined to levels close to the national forest mean. Consequently, the elevated spring and autumn Q₁₀ values drove the high annual temperature sensitivity (3.92). Soil carbon emissions totaled 487.09 g C m⁻² yr⁻¹, with 84.84 % released during the complete thawing stage. Compared with the conventional growing-season and annual Van’t Hoff models, the phase-based model that fitted each freeze-thaw stage separately could reduce the annual soil carbon emission error from 19.3 % to 4.4 %. These findings enable more accurate simulation of carbon-cycle processes in boreal forest ecosystems and support more reliable assessments of permafrost-region carbon-climate feedbacks.