As a kind of metal ceramic material, cemented carbide (WC-Co) has attracted attentions of many scholars for its excellent material property. In this paper, a new method named controlled inclined grinding (CIG) is proposed to fabricate a micro-substrate of cemented carbide. The machining mechanism during CIG was investigated; a lot of micro-substrates, whose diameter is from 8 to 120 μm, had been successfully fabricated; and the critical parameters for obtaining the suitable machining result are given. Two ultra-small micro-tools, with a diameter of 8 μm and 20 μm, respectively, and an aspect ratio (for both) of bigger than 50, had been fabricated by the CIG method. The relationship between tool contour and inclined angle (θ) was revealed, and the optimal inclined angle was found to be 0.5°. Differences when grinding at different wheel positions were studied and compared, and an optimal grinding position was found. A contrast experiment was designed and carried out by using the CIG method and traditional grinding method, and machined workpiece surface was observed by a profilometer and a scanning electron microscope (SEM); it is found that the machined surface of the CIG method was comparatively gentle and even, while the machined surface of the traditional method was violent and uneven. A surface roughness model for the CIG method was built, the corresponding expression was derived, and the surface roughness model was finally validated experimentally. The CIG method proposed in this study is not only a simple device but also cheap and efficient, and it is anticipated to be an optional method to fabricate micro-tool.