The invention discloses a wrench and a preparation process thereof, and belongs to the field of metal materials. The wrench is prepared from a graphite matrix and alloy steel, and the alloy steel is prepared from the following components in percentage by weight: 1 to 3 percent of Ni, 0.5 to 1.5 percent of Co, 1 to 3 percent of Zn, 2 to 4 percent of Mg and the balance of Fe. By adopting a new thought of combination of the graphite matrix and the alloy steel, the strength of alloys is achieved, and the cost of a product also can be reduced. Co in the alloy components is a non-carbide formation element, so that a solid solution strengthening effect is achieved and strengthening of zinc and magnesium is formed; compared with Mg/Zn2, an obvious strengthening effect on the alloys is produced; meanwhile, a method of deposition of all metal elements on the matrix is adopted, so that an aim of thinning crystal grains is fulfilled in processes of cascading, interweaving and winding the all metalelements and combining into the multi-component alloys on the surface of the substrate.