A twist drill with an alloy tool bit, comprising a tool shank, a spiral tool body and an alloy tool bit, wherein the twist drill with the alloy tool bit is integrally provided with at least two spiral tool bodies, the surface of each spiral tool body in the cutting direction is a spiral cutting surface, the surface on the outer side of the backward spiral cutting surface in the rotating direction is a spiral secondary cutting surface, the spiral cutting surface is intersected with the spiral secondary cutting surface to form a spiral cutting edge, the surface on the back side of the axial front end of the spiral cutting surface is a rear cutting surface, the rear cutting surfaces on at least two sides are intersected to form a chisel edge, the spiral cutting surface is intersected with the rear cutting surface to form a cutting edge, and the spiral secondary cutting surface is intersected with the rear cutting surface to form a side edge; the twist drill with the alloy tool bit is integrally composed of the tool shank and the spiral tool body, a groove is milled on the front spiral cutting surface of the spiral tool body, the alloy tool bit is integrally arranged on the front spiral cutting surface, the spiral cutting surfaces on the two sides and a cutting surface of the alloy tool bit are arranged in the same groove respectively, the spiral cutting edge extends to the alloy tool bit to form a secondary cutting edge, and the spiral secondary cutting surface extends to the alloy tool bit to form a secondary cutting surface; a central stepped platform is arranged on the cutting surface near the axial center of the alloy tool bit of the twist drill with the alloy tool bit in a standing mode; a central stepped surface is arranged on the inner side of the central stepped platform protruding in the rotating direction; the central stepped platform is intersected with the rear cutting surface to form a side micro edge; the central stepped platform is intersected with the central stepped surface to form a central edge; the rear cutting surface is intersected with the central stepped surface to form a cutting middle edge; and characterised in that the width of the central stepped surface on the alloy tool bit from the axial center to the cutting surface is smaller than or equal to one third of the radius of the twist drill with the alloy tool bit. the surface on the back side of the axial front end of the spiral cutting surface is a rear cutting surface, the rear cutting surfaces on at least two sides are intersected to form a chisel edge, the spiral cutting surface is intersected with the rear cutting surface to form a cutting edge, and the spiral secondary cutting surface is intersected with the rear cutting surface to form a side edge; the twist drill with the alloy tool bit is integrally composed of the tool shank and the spiral tool body, a groove is milled on the front spiral cutting surface of the spiral tool body, the alloy tool bit is integrally arranged on the front spiral cutting surface, the spiral cutting surfaces on the two sides and a cutting surface of the alloy tool bit are arranged in the same groove respectively, the spiral cutting edge extends to the alloy tool bit to form a secondary cutting edge, and the spiral secondary cutting surface extends to the alloy tool bit to form a secondary cutting surface; a central stepped platform is arranged on the cutting surface near the axial center of the alloy tool bit of the twist drill with the alloy tool bit in a standing mode; a central stepped surface is arranged on the inner side of the central stepped platform protruding in the rotating direction; the central stepped platform is intersected with the rear cutting surface to form a side micro edge; the central stepped platform is intersected with the central stepped surface to form a central edge; the rear cutting surface is intersected with the central stepped surface to form a cutting middle edge; and characterised in that the width of the central stepped surface on the alloy tool bit from the axial center to the cutting surface is smaller than or equal to one third of the radius of the twist drill with the alloy tool bit.