An adaptive-optics OCT retina imager using a coherence-gated wavefront sensor comprises a light source, a polarizer, a first broadband polarization light splitting prism, a second broadband polarization light splitting prism, a first lambda/4 wave plate, a second lambda/4 wave plate, a first broadband light splitting plate, a second broadband light splitting plate, a deformation mirror, a two-dimensional scanner, a microlens array, a first polarization analyzer, a second polarization analyzer, a wavefront detector, a reference mirror, an imaging detection module, a data acquisition card, a computer, a function generation card, a high-voltage amplifier and the like. By adopting the coherence-gated wavefront sensing technology, the adaptive-optics OCT retina imager collects and corrects wavefront aberrations of an imaged layer in a retina and therefore filters wavefront aberrations produced by other layers and devices in an optical path, and transverse resolution close to the diffraction limit is obtained; besides, the Fourier domain OCT technology comprising spectral domain OCT and sweep frequency OCT is adopted for conducting high-resolution longitudinal tomography of the retina. The adaptive-optics OCT retina imager has the advantages that wavefront detection is insensitive to stray light, the strength of wavefront detection signals can be enhanced, and the external dimension of the adaptive-optics OCT retina imager is reduced.