Measuring the moisture content is a problem in preservation of textile, paper, bamboo, wood, leather and stone relics. People usually only measure the moisture of environment, but there is a lack of moisture meter for relics up to now. Model AD-100 meter has been designed for harmless measurement of wood moisture content. Based on the principle of high frequency electromagnetic wave, it rapid measures moisture content according to variation of medium factor without inserting probes or damaging wood. According to the national standard of Determination of moisture content of textile – oven drying method, Paper: determination of water and Leather: determination of water, the measured values of AD-100 for medium was calibrated. Thus the moisture rate of relics can be measured with intactness, briefness and convenience. Using the calibration methods proposed in this paper, moisture rate of relics can be measured for un-calibrated relics material.