Pore structure and pore size distribution are key properties of stone relic and building materials. In the past, Got pore size distribution of porous materials by mercury intrusion porosimetry, which was a laboratory method, and damage for samples. Transverse NMR relaxation also could get pore information of stone relics, Relaxation times and relaxation time distributions of the protons from water saturated samples were measured by low - field NMR using homogenous and inhomogeneous fields, the advantage of NMR measurement are more quickly, easily and attrition small, the NMR - Mouse could by very portable, it can be operated on 24 V from a car battery, as an invasion and harmless technology, it was irreplaceable for immovable cultural heritage protection in situ. Pore size and its distribution are characterized by rock mechanics, physical properties of water. As the same lithology, the higher the porosity, the worse of physical properties of stone. Thus, the porosity and pore distribution could assess stone's weathering. Based on this premise, the different depths of the pore size distribution of stone relics was research by transverse NMR relaxation, and to explore the extent and depth of weathering of stone relics. The results show that through portable NMR - Mouse and homogeneous fields research , the average pore radius of three categories were all increased , and the large pores the most obvious ; three categories pores , the number of small and large pores were significantly increased , however, the proportion of micropores of the total were reduced as weathering enhanced; the result of profile test of weathering stones was 5mm, the good correlation of weathering and pore size distribution could be indicators of weathering classification and weathering depth research. It can be predicted, application transverse NMR relaxation obtained the pore structure of stone relics has broad prospects.