The history of the use of Chinese characters in Vietnam can be said to be the history of Vietnam. This is because of the influx of Chinese characters into Vietnam which began in 207 B.C. when a Chinese official from the Qin dynasty established Vietnam's first ancient state. The long history of Chinese characters in Vietnam has had a profound influence on the Vietnamese language and the language culture of the Vietnamese, and is exemplified by Vietnamese idioms in Chinese characters. The Vietnamese idioms in Chinese characters are somewhat different in form and meaning as Chinese idioms were introduced into Vietnam and translated into Vietnamese. Therefore, it can be said that Vietnamese idioms in Chinese characters contain characteristic elements of Vietnamese language and Vietnamese culture. Given these circumstances, the characteristics in form and meaning of Vietnamese idioms in Chinese characters are classified into three types referred to in this paper as isomorphic synonym types, homonymous types, and heteromorphic synonym types.