Emotion often explains many behaviors in our life. Besides rational reason, many behaviors result from what we have felt. Because of that it is very important to express our feeling and to distinguish others' emotion. In this paper we studied idiomatic emotion expressions to see how the structure contributes to express emotion. As a result we found follow three. First, usually idiomatic emotion expression use 'Nominative noun + Predicate' structure to show emotion's spontaneous property. This type occupies nearly 70% of those idioms. Second, 'Accusative noun + Predicate' structure is effective in showing the Experiencer's activeness and the emotion's intense. Third, 'Noun phrase' and 'Verb phrase' are also used for emotional expression. They can describe some situations, but it is very rare.