The experimental research on the wear mechanics and the tool life of TiN coated cemented carbide cutting tool in high speed milling of the Rogers/ Duroid RT6010 aluminum base microwave printed circuit board is carried out in his paper. The SEM is used to observe the wear morphology of the rake and flank face of cutting tools. The wear mechanisms of TiN coated tool include abrasive wear, adhesive wear and diffusion wear. It is shown that the abrasive wear is the main reason of cutting the complex material. In this paper, the wear mechanisms are an analyzed in details. The research results are contributive to choose proper high-speed cutting tools and parameters.