The invention relates to a preparation method of WC-Co hard alloy for a mine. Primary WC, regenerative WC and Co powder are used as raw materials, wherein the regenerative WC comprises the following elements: less than or equal to 0.1% of Ti, less than or equal to 0.1% of Cr, less than or equal to 0.05% of V and 6.06%-6.20% of C and the ratio of the raw materials accounting for regenerative WC is a, which meets the following formula: a is equal to a quotient of (Hc target-Hcp primary) divided by (Hcp regenerative-Hcp Primary) and multiplied by 100%, wherein Hc target is a target value of a coercive force of the raw materials and the Hcp Primary and the Hcp regenerative are respectively coercive force values of primary WC and regenerative WC. The hard alloy prepared by the preparation method disclosed by the invention has average grain size of 1.6 to 3.0 microns, alloy hardness greater than 87HRA and bending strength greater than 2800MPa, meets the comprehensive performance requirements of a spherical crown alloy for a mine and can be used in the field of mine drilling application and thus the application range of regeneration WC is expanded.