This study was carried out to test the possibility that tracheid length of red pine growing in Sokwang-ri in Uljin could be used as one of variables to estimate its wood properties. For the study, forest stands of V (500 m a.s.l.) and VIIII (900 m a.s.l.) age class plots were selected in the region, and three trees in each plot were investigated. The tracheid length was separately measured for early- and latewood. It took approximately 25 and 40 years for V and VIIII age class stands, respectively, until the length was stabilized. The lengths in latewood were 3.14 (V age class) and 3.30 (VIIII age class) mm, and in earlywood 2.98 (V age class) and 3.15 (VIIII age class) mm. The lengths in latewood therefore were longer than in earlywood and the lengths for VIIII age class were longer than for V age class. However, the ratio between their lengths in early- and latewood was the same as 0.96 in all age classes. It might be verified whether this ratio can be used as a variable to test the wood property according to provinces by comparing it with others.