A foldable miter saw, comprising: a base unit comprising a front edge, a rear edge opposite to said front edge, a bottom wall extended from said front edge to said rear edge, and a top wall opposite to said bottom wall; a worktable mounted at said base unit, said worktable comprising a working surface disposed opposite to said bottom wall and corresponding to said top wall and an axle holder facing toward said rear edge and connected to said working surface, said axle holder comprising an axis disposed in parallel to said working surface and extending from said rear edge toward said front edge; and a cutting unit comprising a support arm pivotally connected to said axle holder of said worktable and biasable relative to said base unit and said worktable, a saw blade mounted at said support arm, and a driver mounted at said support arm and adapted for driving said saw blade to rotate, said saw blade comprising a first end face and a second end face opposite to said first end face, characterized in that the support arm is turnable about said axis to pivot the saw blade between working positions within a contained angle of 90° to 45° formed between the saw blade and the worktable, wherein, said support arm is further turnable about said axis relative to said base unit and said worktable to convert said cutting unit from said working positions to a folded position; in the folded position, the saw blade is outside the contained angle of 90° to 45° and said second end face of the saw blade is located in proximity to said working surface and facing toward said working surface, and wherein, the support arm is lockable in said working positions and in the folded position. a base unit comprising a front edge, a rear edge opposite to said front edge, a bottom wall extended from said front edge to said rear edge, and a top wall opposite to said bottom wall; a worktable mounted at said base unit, said worktable comprising a working surface disposed opposite to said bottom wall and corresponding to said top wall and an axle holder facing toward said rear edge and connected to said working surface, said axle holder comprising an axis disposed in parallel to said working surface and extending from said rear edge toward said front edge; and a cutting unit comprising a support arm pivotally connected to said axle holder of said worktable and biasable relative to said base unit and said worktable, a saw blade mounted at said support arm, and a driver mounted at said support arm and adapted for driving said saw blade to rotate, said saw blade comprising a first end face and a second end face opposite to said first end face, characterized in that the support arm is turnable about said axis to pivot the saw blade between working positions within a contained angle of 90° to 45° formed between the saw blade and the worktable, wherein, said support arm is further turnable about said axis relative to said base unit and said worktable to convert said cutting unit from said working positions to a folded position; in the folded position, the saw blade is outside the contained angle of 90° to 45° and said second end face of the saw blade is located in proximity to said working surface and facing toward said working surface, and wherein, the support arm is lockable in said working positions and in the folded position.