The utility model discloses a plastic template clamp for a building. A plywood comprises a door-shaped fixing plate and a movable plate, wherein the movable plate is arranged between two side plates of the door-shaped fixing plate; a reducing diameter screw bolt, which is inserted from the right side, and a locating rod, which is inserted from the left side, are arranged in a reserved hole in the center of the movable plate; the locating rod is screwed with the reducing diameter screw bolt inside the reserved hole; the diameter of the connection part shrinks to fix the movable plate; the reducing diameter screw bolt is screwed inside from a threaded screw bolt reserved hole in the right side plate, and drives the locating rod and the movable plate to rotate and move leftwards; the movable plate and the left side plate tightly clamp heels of two adjacent plastic templates to realize fixing of the templates. According to the utility model, the plastic template needs not to be hammered during fixing, so that the supporting accuracy of the template is not affected by the vibration generated by a hammer; the mounting and dismounting can be completed by only a hand holding the clamp, and the mounting and dismounting are convenient; the locating rod can prevent two plastic building templates from being staggered; the reducing diameter screw bolt is screwed inside continuously to cause the movable plate to be close to the left side plate, so that the two building templates are tightly clamped.