The process of fabricating low-density blazed gratings is presented. Some novel improvements have been reported, which lead to gratings with better quality. In experiment, 40 μm period blazed gratings with uniform surface are obtained, and the diffraction efficiency of the first order is more than 70%. Compared with traditional method, the efficiency is increased by 5%～10%. Finally, the efficiency of experimental results is compared with theory value, and the reasons of experimental errors are given. It is found that if tips introduced by experiment errors can be removed, the efficiency will be increased greatly, which provide bases on getting better gratings and higher diffraction efficiency.