The invention provides a small broadband circular polarized antenna working in odd and even modes. The antenna comprises a metal oscillator, a feed layer and two metal probes. An open circuit groove and two feeding points are arranged in/on the metal oscillator. When common-mode feeding is performed on excitation signals, a plane reverse F antenna mode can be stimulated. When difference-mode feeding is performed on the excitation signals, a groove antenna mode can be stimulated. Through the polarization orthogonality of the two working modes, the feeding layer provides 90 degrees of phase difference to excitation signals in the common-mode and the difference mode, so radiation characteristics of the broadband circular polarization can be obtained. The antenna is advantaged in that 1) through one short circuit metal oscillator with an open groove, two kinds of quarter-wave resonance modes of orthogonal polarization are generated; and 2), the two working modes share a radiation mouth face, so the utilization rate of the mouth rate is improved. According to the invention, small, low-profile, broadband, high-efficiency and low-cost circular polarization characteristics can be achieved.