The spin polarized transport through double quantum dots embedded in one arm of an A-B ring coupled to ferromagnetic leads has been studied in this paper. The Keldysh nonequilibrium Green function method is used to calculate the total tunneling current, the spin up current, the spin down current and the spin accumulation. The magnitude of them can be modulated by adjusting the polarization, the bias voltage and the magnetic flux in parallel and antiparallel configuration. With the spin-polarization strength P increasing, the total tunneling current decreases in both parallel and antiparallel configuration, and the tunneling for spin up and spin down electrons are different in two configurations. By tuning the magnetic flux, obvious interference between the two different paths can be observed. The spin accumulation in both QDs in antiparallel configuration is also investigated, and increases with the increase of P.