Phlogopite-based geopolymer was first prepared successfully under the activation of lye by compression molding at 50 MPa for 1 minute. The geopolymer was endowed with nonpolar surface via brushing modified liquid at room temperature. Swill-cooked dirty oil, whose main component was fatty acid, was used as nonpolar modifier. The raw materials and geopolymer samples were characterized by XRD, FT-IR and SEM. The compression strength of 7-day specimen run up to 36.8 MPa and its surface static water contact angle could reach 132°. The solubility of phlogopite powder directly affected the compressive strength of geopolymers and the evaluation index of mechanical strength of geopolymer based on the solubility of phlogopite powder was proposed.