The technology of length-alterable line-scanning laser sintering was introduced. Based on the research of laser heating property,powder thermal physics parameters and laser sintering process,a numerical model of the temperature field during length-alterable line-scanning and laser sintering of polymer-coated molybdenum powder was presented. Finite element method (FEM) was used to simulate the temperature field during laser sintering process. In order to verify the simulated results,a measuring system was developed to study the laser sintering temperature field. Infrared meter was introduced to measure the surface temperature of sintering powder:the temperature of its inside part was measured by thermocouple. The measured results were compared with the numerical simulation results:the conformity between them is good and the relative error is less than 5%.