Chinese Character studies have mainly been focused on four areas: orthography, phonology, meaning, and character frequency. To add a new dimension to the existing approaches, this paper will provide and examine a quantitative data about the range of the vocabulary in Chinese character dictionaries. As a promising new method, the new approach, both diachronic and dynamic, will be very useful in exploring changing aspects of Chinese Characters usage, compared with the existing synchronic and static approaches. This paper aims to provide analysis of all Chinese Characters included in Chŏnun-okp'yŏn, the most authoritative dictionary of Joseon dynasty published in 1805 meaning ‘Chinese Rhyme Dictionary’, and in Sinjajeon, meaning ‘New Dictionary of Chinese Characters’ published in 1915, to explain their changing aspects in the entries of two dictionaries, and then to show how social change affected the use of Chinese Characters in early twentieth-century Korea. To that end, I construct the database of the two dictionaries on the basis of a detailed analysis of all the characters with respect to the radicals, strokes, components, and structures of these characters, which shows that Chŏnun-okp'yŏn includes 10,997 Chinese characters and Sinjajeon contains 13,348 characters with 13,084 in the body text and 264 in three appendices. 2,114 characters were newly inserted and 7 characters were removed in the body text of Sinjaeon. In particular, the number of the radical headings containing more than 20 newly inserted characters are 35, with 1,624 new characters in total, accounting for 77.1% of the total. The total number of radical headings including more than 30% newly inserted characters are 26. In addition, the number of radical headings containing more than 10 newly inserted characters with a growth rate of more than 20% is 903, accounting for 43% of the total number of characters. Based on these data, modern Koreans appears to have a wider vocabulary consisted of Chinese characters. The number of characters under the radicals meaning animal and plant ( 犬 (dog), 牛 (cow), 肉 (meat), 木 (tree), 米 (rice), 禾 (pine), 田 (farmland), 虫 (insect) etc.), those meaning mineral (石 (stone), 玉 (jade), etc), those meaning industrial products (皮 (leather), 巾 (towel) ect.), those meaning pathology (疒 (illness), 歹 (broken bones), etc.), increased quite a bit, the words reflecting newly emerged phenomena of industrialization or modernization in the early 20th century. In addition, it can be pointed out that the words used for spoken Chinese newly appears in Sinjaeon.