The invention discloses a silicone rubber microporous foam material adopting a mixed cellular structure and a preparation method of the silicone rubber microporous foam material. The preparation method is characterized by comprising the following steps: mixing 100 parts of a silicone rubber base material, 15-45 parts of a reinforcing agent, 2-3 parts of a structure controlling agent, 60-125 parts of a pore-forming agent and 3-5 parts of a radiosensitizer, forming, radiating through gamma rays so as to enable the formed product to be crosslinked, wherein the radiation absorbed dose is 30-70 kGy, performing solventing-out section by section to form holes, and drying, so as to obtain the silicone rubber microporous foam material with excellent performance. According to the invention, the method that radiation crosslinking cooperates with solventing-out hole forming is adopted, so that crosslinking is uniform, control is convenient, energy conservation and environment friendliness are realized, the process is simple, reproducibility is good, and production efficiency is high; the prepared silicone rubber microporous foam material adopts the mixed cellular structure, and is excellent in comprehensive performance, small in hole, pure white in color, soft in texture, proper in crosslinking density and gel content, high in tensile strength and elongation at break and low in permanent tensile deformation and compression deformation.