Abstract: The structural strength of soft coal seams is low, and during drilling, problems such as hole wall collapse and stuck or buried drill bits are prone to occur, which greatly affects the mining efficiency. The air screw drilling process uses air as the circulating medium, causing less disturbance to the hole wall. Compared with liquid flushing fluid, there is no liquid column pressure, and the hole wall is less likely to collapse, making it suitable for drilling in soft coal seams. However, long-term practical results show that the air screw drilling technology still has problems such as severe dust pollution, short drill bit life, and difficulty in hole cleaning. To solve the problems existing in the air screw drilling technology, this paper proposes a new idea of using foam flushing fluid instead of air as the circulating medium to form an air screw foam drilling process. The Waring-Blender was used for replacement. According to the performance index and compressive resistance requirements of the foam flushing fluid system for air screw foam drilling in soft coal seams, the foaming agent, stabilizer, anti-pollution agent, and anti-compression agent were selected respectively, and the optimal dosage of each treatment agent was determined through orthogonal replacement analysis. On this basis, the foaming volume, half-life, rheological properties, anti-pollution performance, compressive resistance, and rock-carrying performance of the constructed foam flushing fluid system were comprehensively evaluated. The results show that the optimal formula of the foam flushing fluid system is: water + 1.3% AMS + 0.5% CMC + 1% MP + 0.3% HS plant gum. The foaming volume reaches 5.3 times, and the foam half-life is 160 minutes, with large foaming volume and stable foam. The dynamic-plastic ratio reaches 0.91, with good shear thinning and rock-carrying performance. The coal powder sedimentation speed is reduced by 96.9% compared with clear water. The anti-pollution replacement results show that the system has strong resistance to groundwater pollution and coal powder pollution. When the brine addition is 30%, its foam comprehensive index (FCI) can still reach 10642.5; when the coal powder addition is 30%, its FCI reaches 22 050 min·mL. The research results provide a solid technical support for the application of the air screw foam drilling process in gas drainage holes in soft coal seams.