Abstract: Relationship between energy material volume density and volume CT gray value was studied by micron focus volume computed tomography and synchronized detection.The measuring method for energy material density in narrow range was explored.The result showed that the 0.1%diversity of specimen volume density could be distinguished.The Linearly dependent coefficient of specimen volume dengsity and volume CT gray value approached 0.999,while the diversification range of PBX specimens dengsity within 2.5%.