Porous Zn O was obtained by hydrothermal method.The results of scanning electron microscope revealed the porous structure in the as-prepared materials.The acetone sensing test results of porous Zn O show that porous Zn O possesses excellent acetone gas sensing properties.The response is 35.5 at the optimum operating temperature of 320?C to 100 ppm acetone.The response and recovery times to 50 ppm acetone are 2 s and 8 s,respectively.The lowest detecting limit to acetone is 0.25 ppm,and the response value is 3.8.Moreover,the sensors also exhibit excellent selectivity and long-time stability to acetone. Porous Zn O was obtained by hydrothermal method. The results of scanning electron microscope revealed the porous structure in the as-prepared materials. Acetone susceptible test results of porous Zn O show that porous Zn O possesses excellent acetone gas sensing properties. The response is 35.5 at the optimum operating temperature of 320 ° C to 100 ppm acetone. The response and recovery times to 50 ppm acetone are 2 s and 8 s, respectively. The lowest detection limit to acetone is 0.25 ppm, and the response value is 3.8. Moreover, the sensors also exhibit excellent selectivity and long-time stability to acetone.