The invention discloses a double-worktable-exchange device of a laser cutting machine, and belongs to the technical field of laser cutting machines. The double-worktable-exchange device comprises a first worktable and a second worktable, wherein the first worktable and the second worktable are arranged on a worktable rail of a lathe bed, and position exchange of the two worktables is achieved through driving of a chain transmission mechanism. The worktable guide rail is divided into a lifting worktable outer guide rail with the middle high and the two ends low, a lifting worktable inner guide rail with the middle high and the two ends low, and a linear horizontal movement worktable guide rail, wherein transition of each middle high section and the corresponding low sections at the two ends is achieved through inclined sections. Two front side wheels at one end of the second worktable are arranged on the lifting worktable outer guide rail, and two rear side wheels at the other end of the second worktable are arranged on the lifting worktable inner guide rail. The first worktable is arranged on the horizontal movement worktable guide rail. The device does not need to be provided with a lifting mechanism, exchange between the two worktables can be completed by only reasonably designing the guide rails where the worktables operate, the structure is greatly simplified, the manufacture cost is reduced, and the double-worktable-exchange device has the beneficial effects of being convenient to operate and easy to maintain.