A layer of powder material is laid on the upper surface of the formed part by powder laying and heated to a temperature just below the sintering point of the powder. The control system controls the laser beam to scan on the powder layer according to the cross-sectional profile of the layer. The temperature of the powder is raised to the melting point, sintered and bonded with the molded part below. After the completion of a layer, the worktable drops a layer of thickness, and the paving roller spreads a layer of uniform dense powder on the top, and sintering of a new layer of cross section until the whole model is completed.