The invention discloses an organosilicon coating rubber for rail transit, and a preparation method thereof, and belongs to the technical field of silicone rubber application, wherein the organosiliconcoating rubber comprises: 60-80 parts of hydroxyl-terminated polydimethylsiloxane, 10-20 parts of a reinforcing filler, 10-20 parts of an adhesive film reinforcing agent, 4-8 parts of a cross-linkingagent, 1-5 parts of a chain extender, 0.02-0.5 part of a catalyst, 1-4 parts of a tackifier, and 0.8-3 parts of an antifungal agent, and is prepared through heating drying, vacuum defoaming, vacuum mixing and other steps. According to the present invention, the organosilicon coating rubber is a ketoxime removing type one-component room temperature vulcanized organosilicon elastomer, is used for rail transit, can effectively achieve the effects of water resistance, dust resistance, mildew resistance, insulating protection and the like on the outer layer, can solve the mildew problem of the existing organosilicon coating rubber, can achieve the mildew-resistant grade of 0 grade, does not contain volatile solvents such as petroleum ether, solvent gasoline, toluene and the like, and is safe and environmentally friendly, and the cured rubber layer has good strength and good toughness.