Quasars are very important in materializing the reference frame. The excess emission of AGNs (active galactic nuclei) in the mid-infrared band can be used to identify quasar candidates. As extremely distant and point-like objects, quasars also could be further selected by astrometry method. Increasing the number of reliable quasar candidates is necessary in characterizing the properties of Gaia astrometric solution and evaluating the reliability of Gaia's own quasars classification. We identify quasars by using appropriate AllWISE [W1-W2] color and different combinations of astrometric criteria. Together with the contamination and completeness, the magnitude, astrometric properties, density distribution, and the morphological indexes of these selected quasars are evaluated. We obtain a quasar candidate catalog of 1503373 sources, which contains 1186690 candidates (78.9%) in common with the Gaia EDR3_AGN catalog and 316683 newly identified quasar candidates. The completeness of this catalog is around 80% compared to LQAC5, and the purity of the overall catalog is about 90%.