We report on a new method to achieve the single-scan polarization-resolved degenerate four-wave mixing (DFWM) spectroscopy in a Rb atomic medium using a vector optical field, in which two pump beams are kept linearly polarized and a vector beam is employed as the probe beam. As the polarization and intensity of the DFWM signal are closely dependent on the polarization state of the probe beam, a vector probe beam with space-variant states of polarization is able to generate a DFWM signal with space-variant states of polarization and intensity across the DFWM image. Accordingly, the polarization-resolved spectra can be retrieved from a single DFWM image. To the best of our knowledge, this is the first time that the single-scan polarization-resolved spectrum detection has been realized experimentally with a vector beam. This work provides a simple but efficient single-scan polarization-resolved spectroscopic method, which would be of great utility for the samples of poor light stability and fast optical processes.