The invention discloses a high-conductivity free-cutting Cu-SE-Li alloy material and a preparation method thereof, which is characterized by comprising the following chemical components by weight percent: 0.1-0.8% of Se, 0.02-0.1% of Li and the balance Cu. The alloy material is prepared according to the following processing steps and processing parameters: smelting an electric furnace channel, covering by wood charcoal for heat preservation, and gradually adding 99.88-99.10wt% of industrial pure copper; and melting down solid copper, adding 0.1-0.8% of Se element in the furnace for smelting for 50-70min when the temperature of the copper liquid raises to 1195-1220 DEG C to enable Se to be evenly distributed in the copper liquid, adding 0.02-0.1% of Li element, after 15-25min, crystallizing at the temperature of 1150-1180 DEG C in a crystallizer, cooling an ingot, and then heating the ingot to the temperature of 800-850 DEG C to obtain various sections by hot extrusion or cold drawing.