The invention belongs to the technical field of building materials, and provides high-performance facing mortar and a preparation method thereof. The high-performance facing mortar is prepared from white Portland cement, sulphoaluminate cement, superfine gypsum powder, calcium sulfate whiskers, superfine slag powder, high-activity metakaolin, modified styrene-acrylic emulsion, terpene emulsion, anair entraining agent, an antifoaming agent, a wetting agent, a water repellent, a leveling agent, an inorganic pigment and quartz sand. The preparation method comprises the following steps: mixing white Portland cement, sulphoaluminate cement, ultrafine gypsum powder, calcium sulfate whiskers, superfine slag powder and high-activity metakaolin, then adding other raw materials, conducting mixing,adding water accounting for 20-25% of the total weight of the high-performance facing mortar, and conducting uniform stirring before usage. The high-performance facing mortar provided by the inventionhas good physical and mechanical properties and decorative properties; in particular, the frosting problem of the facing mortar is practically solved, the facing mortar is endowed with excellent stain resistance, and the high-performance facing mortar can meet the use requirements for adjustable setting time and operable time and improves construction efficiency.