The idiom is the fixed phrase with the traits of stable patterns, habitual uses, historic and ethnical characteristics. The numeral idiom, as an important part of the idiom, is a special language phenomenon. There are considerable numeral idioms in the Korean language and Chinese language. Although a considerable of the Korean numeral idioms generated from Chinese numeral idioms, however, due to various factors such as different historical background, customs, and language structure, in the long term, Korean and Chinese numeral idioms formed different characteristics in many aspects. This paper mostly examines the grammar structure form of numeral idioms in Korean and Chinese. The aim is to summarize the different system of Korean and Chinese by analyzing the grammar structure rules of the numeral idioms in Korean and Chinese.