The invention relates to a device for generating vector light beams by utilizing a multi-flaw photonic crystal microcavity. A two-dimensional panel photonic crystal structure is adopted, the device is formed by ventages formed in a panel, the multi-flaw microcavity of the structure is realized by removing a plurality of ventages, formed flaw cavities are distributed symmetrically by surrounding the center of the microcavity, and the adjacent flaw cavities are separated by a row of ventages. The method has the beneficial effects that the multi-flaw microcavity is introduced by enabling the ventages to be removed symmetrically in a two-dimensional panel photonic crystal, a resonance film is formed in a panel photonic crystal plane, and resonance optical field scattering is caused by mode mismatching at the junctions of flaws and ambient ventages. The device can be used for the design and development of novel electric appliances.