Abstract: Systemic functional linguistics, as a tool of discourse analysis, provides operable analytical frame for Eco-discourse analysis. The explorations of the ecological implications in William Wordsworth's I Wandered Lonely as a Cloud from the angles of transitivity, appraisal and theme show that, as an eco-benefical discourse, in I Wandered Lonely as a Cloud, Wordsworth's positive ecological view is mainly expressed by Actor's agency in material process, positive appreciation from attitude resources and the choice of theme related to non-human.