A confocal-interference-based chromatography phase microscopic method and device are disclosed. The device includes a laser, a scanning galvanometer system and a first beam splitter which are arranged in order. A laser beam is split by the first beam splitter into reference light and sample light. A lighting lens used for converting lighting light into parallel light and lighting a sample and an imaging lens used for receiving sample light reflected by the sample are arranged in order along a sample light path. A first reflector changing the optical distance of a reference light path by periodically moving the position itself, a compensator used for compensating the optical distance difference between the reference light path and the sample light path, a second beam splitter used for performing beam combination on the reference light and the sample light reflected by the sample, and an image collecting unit used for recording interference images generated by the reference light and the sample light are arranged in order along the reference light path. The device also comprises a computer, and the computer, according to a plurality of interference image packs obtained by a plurality of times of sample scanning and recording in each period of the first reflector, solves a three-dimensional refractive index distribution diagram of the sample in the corresponding period.