Abstract: To gain the solutions for stresses of a bar in a wire drawing process and for the maximum shrinkage ratio of the cross-section of a metal bar with different tension compression strength, the problem of wire drawing is analyzed based on Unified Strength Theory. The influence of the tension compression ratio is taken into consideration. As a result, gained are unified solutions for bar stresses under the wire drawing process and for the maximum shrinkage ratio of the cross-section of the metal bar. In the wire drawing process, the drawing and compression solutions of the metal bar are related by a coefficient, which can differentiate the solution of the drawing process from that of compression. When the tension and compression strength of a material are equal, the Mises result is just a special case of the unified solution of metal wire drawing. The maximum shrinkage ratio of the cross-section of the metal bar is affected by the tension compression ratio of the material in wire drawing process. When the tension strength of a material is equal to its compression strength, the Mises result of the maximum shrinkage ratio of the cross-section of the metal bar is a special case of its unified solution, and also its maximum value.