Zinc oxide (ZnO) nanospheres with excellent sensing ability towards formaldehyde were successfully synthesized us-ing a single-capillary electrospinning method. Structural and electrical characteristics of the as-synthesized ZnO nan-ospheres were systematically investigated. The scanning electron microscope (SEM) images clearly display a novel structure of ZnO with pores distributed on the surface of the nanospheres. The results demonstrate that the ZnO nano-spheres possess excellent formaldehyde gas-sensing properties. At room temperature, the response of ZnO nano-spheres to formaldehyde with concentration of 100 ppm is determined to be 126.3. In addition, the ZnO nanosphere sensors exhibit short response time of 30 s and short recovery time of 2 s. These excellent gas-sensing properties make the ZnO nanospheres a promising material for the application in environmental monitoring devices.