The demands for 3D micro-products are increasing. However, few tool materials have been used to for micro-milling of difficult-to-cut-materials. A new type of the Ti(C7N3)-based cermet micro-mill was designed. To verify that the cermet could satisfy the compressive strength of micro-mills, a contact stress distribution model on the round cutting edge of the cermet micro-mill was established. Dynamic fatigue tests of the Ti(C7N3)-based cermet and micro-milling experiments using the cermet and the coated tungsten carbide (WC) micro-mill were carried out. The model indicted the maximum normal pressure on the cutting edge of the Ti(C7N3)-based cermet micro-mill was less than the compressive strength of the Ti(C7N3)-based cermet. Moreover, the cermet had superior fatigue resistance at 500 °C than at room temperature. Also, the Ti(C7N3)-based cermet micro-mill outperformed the coated WC micro-mill in consideration of tool wear, micro-milling force and machined surface quality. Therefore, the Ti(C7N3)-based cermet could be used as the tool material of micro-mill.