Qinghai-Tibet Plateau is the most typically seasonal frozen soil area in China, and the climate change has exerted a profound influence on its soil freeze-thaw cycles and carbon fluxes. To reveal the influence of soil freeze-thaw cycles on the respiration (R_e) in alpine meadow ecosystem, the CO₂ flux and environmental factors were observed using the eddy covariance and micrometeorological measurements on an alpine meadow in the three-river source region (TRSR) from 2016 to 2017. The influences of seasonal freeze-thaw cycles (SFTC) on R_e were discussed. We also analyzed the absolute and relative increments of R_e (ΔR_FTC(p) and R_{FTC (p)}/R_min) induced by diurnal freeze-thaw cycles (DFTC) and the standardized effect size of DFTC on R_e (lnRR_p) during the spring freeze-thaw cycle period (SFTP). The results showed that the R_e maintained a low-level during the frozen period. However, the rise in soil temperature (T_s5) and soil water content (SWC) promoted the conversion of soil organic carbon to CO₂ during the SFTP and thawed period, and the average R_e in the SFTP increased significantly by 65.2% in comparison with the frozen period for two years. The sensitivity of respiration to temperature (Q₁₀) during the SFTP reached 5.53, which was evidently higher than that in other periods. The ΔR_FTC(p)was 0.023 and 0.017 mg CO₂ m^-2s^-1, the R_{FTC (p)}/R_min was 3.90 and 3.39, and the lnRR_p was 0.207 and 0.119 in the SFTP for 2016 and 2017, respectively, which means the DFTC had a significant influence on R_e. The SWC was the most important factor affecting the daily average ΔR_FTC(d), lnRR_d and R_e for the SFTP, and daily soil temperature difference (ΔT_s5) and daily soil minimum temperature (T_s5min) had measurable effects on these parameters. The results suggested that the higher R_e, Q₁₀, ΔR_FTC(p) and lnRR_p during the SFTP might be related to the higher SWC and ΔT_s5 on this meadow in TRSR, and the R_e during the SFTP was particularly sensitive to temperature rise, and was affected by DFTC obviously. Therefore, more CO₂ may be released into the atmosphere during the SFTP on the meadow in TRSR, under the climate warming and more frequent DFTC.