The invention discloses a
metal-
oxide gas sensor based on MEMS (Micro-Electro-Mechanic
System) and a preparation technology thereof. The gas sensor is characterized by comprising an
Si substrate, an insulating layer, two thin-film
resistor heating elements, a rectangular
micro array, a pair of sensitive electrodes and a metallic
oxide three-dimensional multi-level nano-structure produced on the rectangular
micro array, wherein partial Si at the lower part of the Si base is removed in an anisotropic manner through wet
etching; at the front of the gas sensor, the heating elements and the sensitive electrodes are arranged in a
central symmetry and spiral manner, the rectangular
micro array is arranged in the center, and the heating elements, the sensitive electrodes and the rectangular micro array are positioned on the same layer; the heating elements can also serve as temperature detecting elements. According to the invention, the nano-structure synthetized by adopting a hydrothermal method can realize the
bridge type electrical connection through the mutually crossed dendritic structures, and is finally connected with the sensitive electrodes; the arrangement manner of the rectangular micro array is changed, and nano-materials of different types are replaced, so that the
metal-
oxide nano gas sensor based on different measuring circuits and sensitive materials of different types can be processed.