The invention relates to a 3D printing base, in particular to a multifunctional SLS 3D printing variable control base. According to the multifunctional SLS 3D printing variable control base, materialscan be flattened and compacted through a flattening wheel, ascending and descending of the base and the size of the base area can further be controlled through hydraulic pressure, and the sizes of baffles can further be controlled through motors to adapt to change of the base; and a sliding rod is fixed at the upper portions of supports, the supports are arranged two and fixed on the two sides ofthe base, the baffles are arranged two and fixed on pushing plates, a hydraulic control base is fixed inside the base, the flattening wheel is located at the upper portion of the sliding rod, the pushing plates are arranged four, two of the pushing plates are fixed with the baffles together, and the base is quadrate.