The first purpose of this study is to assess the influence of cutting mode parameters on surface roughness and tool wear. The second purpose of this study is to build a relationship between surface roughness and tool wear. The cutting parameters mentioned in this study include the cutting speed, the feed rate and the depth of cut. The experimental material used in this study is steel C45. The cutting tool used is the PVD-coated face milling cutter. Experiment with 15 experimental points according to the Box-Behnken type experiment plan when changing the value of the cutting parameters. Analysis of test results has determined the influence of cutting parameters and their interaction on surface roughness and tool wear. The relationship between surface roughness and cutting parameters, the relationship between tool wear and cutting parameters and the relationship between surface roughness and tool wear are also established in this study. These relationships are the basis for defining cutting parameters to ensure that the surface roughness meets the specific requirement, the tool wear is small, and are the basis for determining when to replace (re-sharpen) the tool according to the specific surface roughness requirements