This study explains a design of the microfabricated planar methanol sensor and conducts a series of methods to achieve a real device. By utilizing the microfabrication technology, it is possible to develop the miniature planar methanol sensor to integrate with direct methanol fuel cells (DMFC). The electrochemically reactive area can be adjusted effectively to obtain adequate strength of the methanol oxidation current. The innovation of the methanol sensor design is on a matrix detecting area with the in-line monitoring functions. Each detecting holes in matrix has been connected together by a serpentine channel to conduct electrochemical reaction at the surface of electrodes. In front side of wafer, the interdigitate electrode design provides a flexible adjustment in the reactive area for modulating the strength of methanol oxidation current. A compatible fabrication of methanol sensor and DMFC has also been proposed in this work. The serpentine channel and detecting holes of methanol sensor are anticipated to be made in opposite side of DMFC fuel channels. Also, the through holes have to be formed by the combination of front-side and backside Deep RIE etching. Both of them require a precise double-side alignment. At the end, a simple planar methanol sensor has been made for verifying electrochemical characteristics and the integration solution with micro DMFC has been discussed to benefit the micro DMFC system development.