The purpose of this study is to analyze usage patterns of the complex words in the Korean educational materials according to the types of the words such as pure Korean words, Sino-Korean words and loanwords. This study also attempts to investigate word-formation units(affix in case of derivative words and the types of roots in caes of compound words) comprising complex words and to identify the word=formation units with high productivity. This study finds several facts based on the analysis as follows. First, the number of vocabulary according to the types of words becomes larger in order of Sino-Korean words, pure Korean words, hybrid words and loanwords, with the number of Sino-Korean words almost doubling pure Korean words. The loanwords and hybrid words also account for a substantial portion of vocabulary population. Second, derivative words account for a particulary higher proportion of suffix derivatives than the compound words in terms of the complex words. Third, in terms of the part of speech distribution of complex words according to types of words, nouns account for the largest proportion in each type of words. However, the proportion of verbs and adjectives varies across the types of words. Verbs and adjectives show the proportion of 1,074/1 and 389/14 respectively and Sino-Korean words come in the form of pure Korean words and hybrid words(116 verbs and 420 adjectives) rather than simple words. Fourth, this study presents the range and frequency over the Korean educational materials by only examining the top 50 individual complex words according to the types of words. The overall frequency of pure Korean words is higher than Sino-Korean words, which indicates that pure Korean words and complex words account for a large proportion of high frequency words. Since this study is analyzed with real data of Korean education field, the results of this study can be used as basic data that are applied in Korean education materials compilation and teaching.