Embodiments of the present invention provide a focusing processing method and apparatus, and a terminal device. The method includes: obtaining (301, 403) a first image collected by n/2 pixel points on a left side of a combination pixel in the second image sensor and a second image collected by n/2 pixel points on a right side of the combination pixel in the second image sensor; determining (302, 404) a phase difference between the first image and the second image and determining whether the phase difference is in a preset range; and controlling (303) a first motor in the first camera assembly to drive a first camera to move according to the phase difference and depending on a preset strategy, if the phase difference is not in the preset range.