This paper aims at many difficulties in view of the igneous rock reservoir appraisal in the lithological recognition, the effective level division, the stratigraphic correlation. Based on studies of the natural GR spectrometry logging characteristic, taking ND area of Santanghu Basin igneous rock reservoir as an example, the researches on the Natural Gamma Ray Spectrometry log in the igneous rock reservoir’s application method are conducted, which obtained good results and can be a good guidance for the next igneous rock oil well logging series optimization.