This study was to analyze the Korean vocabulary proficiency of Chinese students who study at a university in Korea and to provide a discussion about Korean vocabulary acquisition of foreign students. 23 Chinese students participated in three tests for receptive and expressive Korean vocabulary abilities. The words in each test were classified by word-class (noun, verb, adjective), word-type (Sino-Korean word, loanword, native-Korean word), and difficulty level (beginner, intermediate, advanced) and compared with each other. Chinese students had significantly lower scores on the measure of expressive than receptive vocabulary and there was no significant difference between two receptive vocabulary tests. They had more difficulty comprehending (a) verbs than nouns and adjectives, (b) native-Korean words than Sino-Koreans, and (c) advanced than intermediate words. They had more difficulty expressing (a) adjectives than nouns and verbs, (b) Sino-Koreans than native-Korean words, and (c) intermediate and advanced than beginner words. Significant correlations were found between all the vocabulary measures and the length of residence in Korea. The period of learning Korean in Korea was significantly correlated only with expressive vocabulary proficiency. Our findings provided advanced information about Korean vocabulary acquisition in Chinese international students and underscored the need for various approaches to Korean vocabulary assessment and education.