Using small-diameter Daimyo Oak （Quercus dentata） Lumber, the effect of the position in a top-fan kiln on its drying defects was investigated in this paper. The results showed that the differences of the drying defects between the front and back positions were slight, whereas that between the upper and lower positions were significant. The lumber at the upper position in the kiln tended to take more severe bow and crook. Further correlation analysis of the results （revealed）that, the bow and crook of lumber was closely related to positions in the upper-lower （direction）at the level of α=0.05. These results indicated that an improper position could result in more drying defects and even degradation of the lumber.