The invention discloses a linear laser scanning three-dimensional contour measuring method and device. A linear laser device swings under the control of a magnetostriction micrometric displacement controller to form a scanning surface on a detected object, the swing angle omega is determined by the size of the object, and it is guaranteed that the linear laser device completely scans the contour of the detected object; then height information of all contour points is acquired, and the three-dimensional surface contour of the object is reestablished. The linear laser scanning three-dimensional contour measuring method and device have the advantages that in the method, the object does not need to move, the laser device is controlled by the magnetostriction micrometric displacement controller to swing to completely scan the contour of the object, after light rays on which diffuse reflection is conducted by the surface contour of the object are received by an imaging module, the height information of all the points on the surface contour of the object can be acquired, the three-dimensional surface contour of the surface of the object is reestablished, the range and the angle of the laser scanning surface can flexibly change according to the size of the object, measurement is accurate and quick, accuracy is high, the application range is wide, and the three-dimensional contour measuring device is simple in structure and convenient to operate.