The invention discloses high-strength, tear-resisting and antiflaming sheath rubber for a cable. The high-strength, tear-resisting and antiflaming sheath rubber for the cable is prepared from, by weight, 100 parts of chloroprene rubber, 0.5-2 parts of stearic acid, 0.5-3 parts of coupling reagent, 3-12 parts of magnesium oxide, 3-8 parts of zinc oxide, 10-40 parts of white carbon black, 5-20 parts of argil, 5-10 parts of talcum powder, 8-25 parts of fire retardant, 7-16 parts of plasticizer, 1-5 parts of anti-aging agent and 2-5 parts of accelerant. According to a preparation method of the high-strength, tear-resisting and antiflaming sheath rubber for the cable, the chloroprene rubber is plasticated for 5 minutes at the temperature of 60-70 DEG C and stands for more than 12 hours at the normal temperature, then mixing is carried out, half of the white carbon black, half of the argil, half of the talcum powder and half of the plasticizer and the stearic acid are added into plastication rubber and are evenly mixed, the other half of the white carbon black, the other half of the argil, the other half of the talcum powder and the other half of the plasticizer are added 2 minutes later, then mixing is carried out for 2 minutes, finally the accelerant and the zinc oxide are added for mixing, horizontal and longitudinal cutting is carried out, thinning is carried out six times, discharging is carried out after turn-mixing is carried out for 1 minute, and the cable sheath rubber is prepared on a slicing machine. The sheath rubber for the cable has the advantages of being high in tensile strength, high in tear strength, resistant to flame, good in flexibility, resistant to ozone and the like.