The invention provides a controllable expansion extrusion earth device used for geotechnical engineering, comprising an upper sleeve component (1); the top end of the upper sleeve component (1) is fixed with an upper cover plate (2); the upper internal part of the upper sleeve component (1) is provided with an upper elastic sealing part (3); the lower part of the upper sleeve component (1) is connected with the upper opening of the top end of an expansion extrusion cylinder (5); the expansion extrusion cylinder (5) is made of the material which is externally expanded, unfolded and folded when fluid with the pressure less than 8MPa is injected into the expansion extrusion cylinder (5); the upper sleeve component (1), the upper cover plate (2) and the upper elastic sealing part (3) are provided with a pulp injection pipe upper pore (6) and at least a transmission component upper pore (7) which are communicated with the upper opening of the expansion extrusion cylinder (5). The invention aims at providing the controllable expansion extrusion earth device and the applications which are used for the geotechnical engineering and can carry out the reinforcing by injecting pulp, replacing and correcting operation for the foundation in complex stratum, improve the effect, increase the bearing capability of single pile and single anchor and improve the bearing capability of the component in the reinforced body or the soil.