A retina dark field optical coherence tomographic imager for continuous adjustable ring lighting comprises a swept source, a first optical fiber coupler, a second optical fiber coupler, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a first variable diaphragm, a second variable diaphragm, a first axicon, a second axicon, a first translation table, a second translation table, a beam splitting sheet, a vertical scanner, a horizontal scanner, a dispersion compensation sheet, a first polarization controller, a second polarization controller, a balance detector, a first single mode fiber, a second single mode fiber, a third single mode fiber, a fourth single mode fiber, a fifth single mode fiber, a sixth single mode fiber, a seventh single mode fiber, a function generation card, a data collection card, a computer and the like. The imager achieves longitudinal high-resolution tomography of the retina based on a frequency sweeping OCT technology, a ring lighting beam with the size and thickness continuously adjustable is formed through a pair of axicons with cone vertexes oppositely arranged so that dark field lighting is achieved, one variable diaphragm is used for filtering lighting light signals and backward reflected light signals of the lighting light signals, and only dark field light signals from the retina are detected. The retina dark field optical coherence tomographic imager has the advantages that ring lighting is continuously adjustable, and images have the high resolution, the high contrast ratio and the strong stereoscopic impression.