The invention relates to polymer powder material which contains polyamide, a molding method thereof and a die to produce the polymer powder material. The method is characterized in that operation to the powder material is carried out from layer to layer, and each layer can be selectively melted if electromagnetism is introduced. The selectivity (not limited in the invention) can be realized through a mask, inhibitor, absorbent or an acceptor or through the concentration of the introduced energy. After cooling, a molded piece at the hardened area is taken out from the powder bed. The preparation of the polymer powder material of the invention is based on polyamide which contains middle-sized lactam ring. The complex process of extracting the remnant monomer in the polyamide can be omitted.The formation process in the RP/RM method is more reliable and consistent even as for high-level work since the invention basically removes the remnant monomer deposited on an optic component, such as a laser sintering system. The component, particularly the surface of the component, is of good performance, and is of better repeatability compared with the component made with powder material with higher content of remnant monomer.