The accurate and rapid monitoring of xylene gas is highly desired for human health and environmental protection. Herein, bowknot-like CuO architectures have been synthesized through a facile room temperature coprecipitation approach followed by subsequent annealing treatment and applied for volatile organic compounds (VOCs) gas detection. The as-prepared bowknot-like CuO architectures with 3–5 μm in length are assembled by many intersecting granular nanochains. Compared with contrasting nanosheet-constructed flat flower-like CuO, bowknot-like CuO architectures present a faster response/recovery speed (1 s/8 s), higher sensitivity and better selectivity at a lower working temperature. Furthermore, the bowknot-like CuO based sensor shows good repeatability and stability toward xylene gas. Such a preferential enhancement of the xylene gas sensing properties is mainly attributed to the appropriate catalytic activity of p-type semiconductor CuO induced by oxygen vacancy defects and the configuration advantages of granular chain building blocks.