The revised curriculum includes the achievement standard for writing a critique. It is different from the seventh national curriculum. The necessity of the useful teaching method of writing a critique in a class is newly recognized. Writing a critique means to write the contents learners get as audiences with the objective base of literary theory, after they understand and appreciate literary works. The logical basis has the balance between subjectivity and objectivity. Especially, in the case of an ecological poem, it is easy to show the theoretically objective basis because the poem must be appreciated on the basis of background knowledge. This paper is to show how to teach writing a critique by using an poem. First of all, the specific achievement standard represented in the revised curriculum, is studied. And the teaching process of writing a critique is explained in detail. First, a teacher describes the background knowledge related to an poem in order to make students understand it deeply. As they remind and summarize the background knowledge, the summary can be a part of the contents they want to write. Next, they find main poetic dictions and grasp meanings of them by utilizing the literary imagination. Lastly, they compare their writing with critic`s and supplement lack of contents. The education of writing a critique using an poem can be developed into writing a critique about the whole work of art.