Abstract Frost weathering frequently occurs at high-latitude and alpine regions, as well as in winter season at mid-altitude region. The weathering damages to building stones, surface of structures and cultural heritages, and can form distinguishing geomorphology. In this research, microstructure of rock specimen is analyzed using micro X-ray CT and SEM. Using scanning electron microscope (SEM) images, particle detachment, pore connection and crack propagation/expansion were detected, and porosity is analyzed quantitatively. Using X-ray computed tomography, variation on open/closed porosity, pore size distribution, equivalent diameter and local thickness were analyzed. This research can be applied to construction, resources exploitation, prevention of geological disaster, and preservation of historical monuments in cold regions. 1. Introduction Frost weathering frequently occurs at high-latitude and alpine regions, as well as in winter season at mid-altitude region. The weathering damages to building stones, surface of structures and cultural heritages, and can form distinguishing geomorphology. Although there have been many researches to investigate frost weathering, most researchers have focused on variation on physical properties or on the rock surface. The purpose of this study is to evaluate frost weathering of igneous rocks quantitatively using micro-CT and SEM. 2. Methodology 2.1 Sample description Three types of igneous rock were collected in Korea. Basalt, sampled at Cherwon-gun, Gangwon-do, has vesicular texture with needle-shape plagioclase; Diorite, sampled at Goheung-gun, Jeollanam-do, was coarse-grained rock consisting of plagioclase, olivine, micas, quartz and microcline; and Lapilli tuff, sampled at Hwasun-gun, Jeollanam-do, was fine-grained rock with feldspar, quartz, micas, quartzite fragments, and basaltic fragments.