We report the conductance and average current through a triple-quantum-dot interferometer coupled with two ferromagnetic leads using the nonequilibrium Green's function.The results show that the interference between the resonant process and the non-resonant process leads to the formation of Fano resonance.More Fano resonances can be observed by applying a time-dependent external field.As a Zeeman magnetic field is applied,the spin-up electron transport is depressed in a certain range of electron energy levels.A spin-polarized pulse device can be realized by adjusting the spin polarization parameters of ferromagnetic leads.Moreover,the Ⅰ-Ⅴ characteristic curves show that under the influence of Fano resonance,the spin polarization is significantly enhanced by applying a relatively large reverse bias voltage.These results strongly suggest that the spin-polarized pulse device can be potentially applied as a spin-dependent quantum device.