The invention relates to a cone beam CT circular-linear track back projection filtering reconstruction method. M-lines are selected according to the imaging geometry characteristics of a circular-linear scanning track; a back projection integral interval is determined by calculating the endpoint coordinates of an R-line passing through the reconstruction points on the M-lines; and object reconstruction is implemented through Hilbert transform. The problem of cone angle effect during big-cone-angle scanning of a single circular track can be solved effectively. A linear scanning track is added on the basis of circular track scanning, so the conditions of perfect reconstruction are satisfied, and complete reconstruction projection data is obtained. The method can be better applied to actual scanning, effectively improves the quality of an image reconstructed at a big cone angle, and is of important practical significance to the expansion of the application range of cone beam CT scanning.