The invention discloses a soft soil foundation air-water displacement and consolidation method which comprises the following steps of: firstly, drilling a soft soil area requiring reinforcement according to vertical and horizontal layout with the intervals of 5 to 10m; inserting air pipes into boreholes, and connecting the air pipes and cross joint air valves with an air compressors and the air pipes inserted into the boreholes; arranging vertical and horizontal drainage channels between the boreholes; and then pressing air into the boreholes; filling air in the foundation soil layer requiringreinforcement; using air pressure to squeeze out groundwater in the soft soil layer to achieve air-water replacement; when the pressed-in air bursts out from the earth surface, stopping pressing theair into the soil layer and quickly deflating so that non-saturated soil produces compressive deformation under the load action of an overlaying soil layer, thus achieving the aim of reinforcing the foundation soil. By applying the invention, the depth of soft soil foundation drainage consolidation is unrestricted, the engineering cost is low, and project implementation process is simple and convenient, thus quickly producing the reinforcing effect of deep soft soil foundation and being suitable for the reinforcement treatment of complex environment soil foundations including offshore slopes and the like.