The invention provides a copper-based nano-composite structure-based portable micro-glucose enzyme-free sensing electrode as well as a preparation method and an application thereof. The invention provides the high-efficiency sensing electrode based on the porous copper and copper oxide composite material, so that the electrode can be endowed with the excellent conductivity of copper and the excellent catalytic performance of copper oxide; the electrode adopts a three-electrode coplanar system, the size of the electrode is matched with that of a USB, the micro sensing electrode is formed, and the micro sensing electrode can be directly connected with an electrochemical workstation. The NCA / NPC composite electrode provided by the invention is relatively high in sensitivity, extremely low indetection limit, relatively wide in detection range, excellent in stability and anti-interference performance, wherein the sensitivity of the composite electrode is 1621[mu]A / mM.cm2 within the detection range of 0.5-5.0mM, the detection limit is 338nM, the response time is less than 3s, and the electrode can be applied to actual detection of human blood sugar.