The invention provides a smearing machine tool for an expansion link type building steel formwork release agent.The smearing machine tool comprises an expansion link and a smearing head.A handle is arranged at the lower end of the expansion link, a connecting base is arranged at the upper end of the expansion link, the rear end of the connecting base is connected to the expansion link through a movable hinge, and the smearing head is installed on a round installing rod at the front end of the connecting base.The smearing head is composed of a pressing disc and a rotary disc which can rotate relatively.The pressing disc is arranged on the outer side of the rotary disc, and the pressing disc is fixed to the round installing rod and used for limiting the rotary disc.A magnet is arranged in the pressing disc, the diameter of the pressing disc is smaller than that of the rotary disc, and a towel for smearing of the release agent is arranged on the outer side face of the rotary disc.The smearing machine tool is simple in structure and convenient to use; the magnet of the pressing disc can be attracted on the surface of a steel formwork, the pressing disc is dragged, the rotary disc rotates accordingly, the release agent is evenly smeared on the surface of the formwork through the towel on the surface of the rotary disc, and the problem that the color of the concrete surface is not uniform due to the fact that a coating of the release agent is too thick when the release agent is smeared is avoided.