The invention discloses a portable house sandwich panel and relates to the technical field of building materials; a processing method comprises the steps of mixing well foamed polystyrene particles, hollow glass beads, aluminum hydroxide, silica, a flame retardant, and a smoke inhibitor; adding a foaming agent and aluminum sol, and stirring well to obtain viscous colloid; adding water to the viscous colloid, stirring, pouring the obtained slurry into a mold at a speed controlled to 3-6 ml/s, and vibrating the mold under the frequency of 45-60 Hz; after pouring, allowing curing, and applying expansive fireproof coating to the surface of a plate; gluing a colored steel plate and a core plate, assembling to obtain a base plate, pre-pressing the base plate under the pressure of 0.85-1.2 MPa for 1-2 h, and performing hot pressing under the pressure of 0.8-1.2 MPa at 120-130 DEG C. The problem is solved that an existing portable house sandwich plate with low self-weight and high strength iseasily flammable and easily separates.