The invention discloses an optical fiber ribbon strain sensor based on multi-core array gratings. The optical fiber ribbon strain sensor comprises a solidified body and multiple optical fibers arranged in parallel in the solidified body, wherein every two of the optical fibers are parallel to each other, multiple gratings are sequentially arranged on every single optical fiber in the axial direction of the optical fiber, pitches between the gratings on each optical fiber are identical or different, an optical fiber indicating color can be smeared on a coating layer of each optical fiber, eachoptical fiber corresponds to one optical fiber indicating color, and all the optical fiber indicating colors are different. According to the design, structural strength is high, the strain sensor is not prone to being broken, multi-point measurement can be realized, and working efficiency is high.