The invention discloses a soft low-smoke halogen-free flame-retardant polyolefin cable material and a preparation method thereof. The cable material comprises the following components (based on by mass part ratio): 80-90 parts of copolymer of ethylene-vinylacetate, 10-20 parts of linear low-density polyethylene, 65-130 parts of an inorganic fire retardant through surface treatment, 10-30 parts of high-effective flame retardant synergist, 10-20 parts of high molecular compatilizer, 0.9-1.5 parts of antioxidant and 1-2 parts of processing aid. The preparation method comprises the steps of resin blending extrusion; surface treatment of the inorganic fire retardant; batching, mixing, extrusion, granulation and the like. Compared with the prior art, the invention has the characteristics of predominant flame retardation (an oxygen index up to 36), excellent toughness, excellent bending resistance, low density (density is only 1.28g/cm<3>), low smoke, low corrosion, low toxicity, environmental protection, good processability, bright surface of extrudates and the like.