Abstract: The medium-rank coal in China accounts for 37% of the country's coalbed methane resources. Effectively enhancing permeability and desorption rate is the key technical bottleneck for efficient extraction. The supercritical CO₂ pulsating fracturing technology combines the physical effect of fatigue damage caused by pulsating loading and the chemical effect of swelling and extraction by supercritical CO₂, which can specifically solve the problem of fracturing and permeability enhancement for medium-rank coal. Exploring the influence of supercritical CO₂ pulsation on the gas desorption characteristics of medium-rank coal and clarifying its mechanism can provide technical support for gas desorption and efficient extraction in low-permeability medium-rank coal. Using a supercritical CO₂ pulsation fracturing and gas adsorption/desorption experimental system, orthogonal experiments were conducted under different conditions of pulsation time, experimental temperature, pulsation frequency, and coal sample size. Combined with variance analysis, range analysis, and sensitivity analysis, the significance and sensitivity of these four influencing factors were revealed. The results indicate that, through variance/range analysis of the orthogonal experimental results, pulsation time and coal sample size exert a more significant impact on gas desorption capacity and serve as the main controlling factors, whereas the impacts of experimental temperature and pulsation frequency are relatively smaller. The order of significance is: pulsation time > Coal sample scale> pulsation frequency > experimental temperature. Through sensitivity analysis of the orthogonal experimental results, the unit gas desorption amount initially increases and then decreases with pulsation time, reaching its peak at 24 hours. Additionally, the unit gas desorption amount decreases with the increase of coal particle size. Under the condition of determining the optimal pulsation time as 24 hours, comparing the unit gas desorption amounts of coal samples with different particle sizes (75 μm、187.5～250 μm、3～6mm coal powder, and Φ25 mm×50 mm coal pillar) before and after pulsation treatment, the post-treatment unit gas desorption amounts were 2.886, 2.023, 1.880, and 2.420 times higher than those measured before treatment, respectively. During the on-site supercritical CO₂ pulsating fracturing of medium-rank coal, the pulsation time can be set to 24 hours. Meanwhile, when conducting supercritical CO₂ pulsating fracturing on low-permeability coal seams, the influence of coal sample scale on gas desorption should be taken into account.