With the help of KLTER/ME and KLPS in Woraksan, we have surveyed monthly diversity and seasonal prevalence of Macrolepidoptera in Wol-ak-san [Mt.], Jecheon for the period of five months from May to September since 2005. In 2007, to reduce variation, we chose two monitoring points from each of three representative vegetations in the area: Quercus mongolica-, Quercus variabilis- and Pinus densiflora-formations, abbreviated as QM, QV and PD, respectively, and collected exclusively larger moths with bucket-type of light traps for quantified survey. As a result, 1) QM and QV showed the much higher species diversity than PD; 2) in number of individuals collected, QM was the highest, almost twice that of QV, and nearly 8 times that of PD; 3) in Noctuidae and Geometridae collected, QM was the highest, while in Pyralidae and Arctiidae collected, QV was the highest; 4) June was the highest in species diversity, then July was a deep drop, probably due to a storm occurred in July; 5) the number of individuals collected may not be a good indicator as one species may be dominant too much in number of individuals: e.g., Idaea biselata collected in QM in June was over 200, changing the average number of individuals per species to 6.92, which more than twice that of all other sites per month.