The invention discloses a silica-gel-containing sponge mattress which comprises 75-90 parts of polyurethane, 15-20 parts of silica gel, 0.2-0.3 part of silicon oil, 0.1-0.2 part of crosslinking agent, 0.2-0.3 part of foaming agent, 0.1-0.15 part of catalyst, 0.05-0.2 part of foam stabilizer and 1.5-2.5 parts of water. The invention also discloses a preparation method of the silica-gel-containing sponge mattress, which comprises the following steps: weighing the raw material components, grinding the silica gel into granules with the granularity of lower than 100 meshes, evenly mixing all the components, putting into a foaming machine, foaming, cooling, and making the mattress according to the conventional method. By adding the silica gel into the raw materials and combining the advantages of the sponge and silica gel, the prepared sponge mattress feels warm in winter and cool in summer, has the effect of keeping the temperature constant, and is not too cold in cold winter or too hot in hot summer. According to the manufacturing method, the silica gel is ground into the granules with the granularity of lower than 100 meshes, and all the raw materials are mixed, foamed, cooled and prepared into the mattress according to the conventional mattress production method. The method is simple in operation sequence and suitable for large-scale production.