Abstract: NiO/NiCo₂O₄ with microflower composites were prepared by solvothermal method. The morphology, crystal structure, chemical composition and specific surface area of the samples were characterized by scanning electron microscopy（SEM）, X-ray diffraction（XRD）, X-ray photoelectron spectroscopy（XPS） and specific surface area and aperture analysis（BET）. Then, the sensitive properties of acetone were tested by the sensor made of the prepared materials. The experimental results show that NiO/NiCo₂O₄ is formed when the molar ratio of nickel source to cobalt source is 1.5, and the response value of the sensor to 100 ppm acetone at 190 ℃ is 7.4, which is higher than that of pure NiO and NiCo₂O₄, and shows good selectivity and reliable stability. This is attributed to the porous structure of the microflower-like complex providing a convenient channel for gas diffusion, while the large specific surface area provides more reactive active sites for the Redox reaction between acetone and adsorbed oxygen, which improves the gas sensitivity of the sensor to acetone.