In order to recognize the explosion suppression ability of potassium-containing fine water mist in the scenario of gas leakage in urban comprehensive pipeline corridors，the explosion suppression tests were carried out with additive-containing fine water mist located outside the methane-air explosion area by a self-made explosion experimental system. The effects of pure water and fine water mist of three potassium compounds，namely potassium oxalate，potassium carbonate and potassium chloride，on the overpressure and overfire range of 9.5% methane-air explosion were analyzed. The results indicate that the critical explosion suppression atomization concentration range of pure water mist outside the methane-air premixed area is 320-480g/m³. The overpressure decrease rate under potassium oxalate-containing conditions showed a trend of NormalCDF (Normal Cumulative Distribution Function) with increasing mass concentration，and the optimum suppression concentration is 10%. When the atomization concentration is 480 g/m ³，D₃₂ is 61.7 μm，the mass concentration of the compound is 10%，and the explosion suppression ability of water mist containing additives is greater than that of pure water mist. Among them，potassium oxalate has the strongest explosion suppression ability，followed by potassium carbonate and potassium chloride. The peak overpressure reduction rate is 2.32 times，1.88 times，and 1.53 times higher than that under pure water mist conditions，respectively. The range of overfire is reduced by 46.7%，40%，and 13.3%，respectively. Compared to potassium carbonate and potassium chloride，the potassium oxalate fine water mist outside the premixed area could absorb more heat and consume more active free radicals.