Y-doped α-MoO3 nanoarrays constructed by nanorods were simply synthesized by a facile and simple two-step solid-state chemical reaction. X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy were applied to characterize the micro-structures and surface chemical composition of the as-prepared products. The results suggested that Y element had been successfully doped into the α-MoO3 nanoarrays. The gas-sensing behaviors of Y-doped nanoarrays toward seven kinds of harmful gases were also investigated. The results indicated that the Y-doped α-MoO3 nanoarrays display not only an improved response (the response value reaches 28.3 to 100ppm xylene), but also an excellent selectivity to xylene. The good xylene-detecting behaviors were attributed to smaller size and the relative larger surface area. Furthermore, the doping of Y increased the electron donor defects and oxygen vacancies, which accelerated the mobility of oxygen ions and enhanced the conductivity of material, resulting in enhanced response to xylene.