The invention relates to ultraviolet-light deeply cross-linked halogen-free flame-retardant polyolefin cable material and a method for preparing an ultraviolet-light deeply cross-linked halogen-free flame-retardant polyolefin cable insulating or sheathing layer from the same. The method comprises the following steps: adding a metal hydroxide flame retardant, a cationic photoinitiator, a free radical photoinitiator, a multi-functional cross-linking agent, a compound antioxidant, a flame-retardant synergist, a synergistic smoke suppressant and a processing aid to polyethylene or grafted and modified polyethylene and / or ethylene vinyl acetate or grafted and modified copolymer thereof which are used as base materials, compounding, mixing the materials uniformly according to the proportion, granulating, extruding to prepare the ultraviolet-light cross-linked halogen-free flame-retardant polyolefin cable insulating or sheathing layer, and immediately irradiating with a specific ultraviolet-light source to obtain the deeply cross-linked halogen-free flame-retardant polyolefin cable insulating or sheathing layer. The cross-linking equipment used for preparing the novel material by using anovel technology has low investment, and the process is simple and environmental friendly, saves energy, ensures high production efficiency and low cost and good quality of product and can be widely used for producing high-performance special wire and cable products and the like.