The utility model provides a base of numerically -controlled machine tool, includes the base, the bottom of base is equipped with the rectangle recess, both sides in the rectangle recess articulate through the pivot has the support arm, the lower extreme of support arm is equipped with the runner, and support arm corresponding position in both sides is equipped with the axle, still includes the central siphon, be equipped with the spring in the central siphon, the both ends of spring are passed through the axostylus axostyle and are articulated with the axle, the limit portion of base is equipped with the cavity, be equipped with the arm -tie in the cavity, the bottom of arm -tie is equipped with logical groove, it is connected with the bracing piece through the round pin axle to lead to the inslot, fixedly connected with pneumatic cylinder on the base of runner limit portion, the bottom of pneumatic cylinder is equipped with the lower margin. The utility model discloses lower margin on the pneumatic cylinder supports the base, makes things convenient for the removal of base through the runner, and the design of arm -tie makes things convenient for putting of work piece, simple and practical.