Mechanical and thermal properties of several kinds of plywoods, which were trially manufactured for the thermal barrier of the LNG carrier, were experimentally proved. Material tests were carried out at room temperature, -78°C (dry-ice) and -196°C (liquid nitrogen). The results are as follows : (1) The obtained coefficients of variation are for the most part distributed within 20 percent and those of Young's modulus around 10 percent. (2) Breaking strength and Young's modulus are proportional to the specific gravity. (3) Breaking strength, proportional limit and Young's modulus have tendency to increase in cryogenic temperature region. (4) Regarding size effect of test specimen, the mean values do not show evident difference, but the standard deviations decrease evidently according to the increase of size.