As one of the most thrilling stories written by Adgar Allan Poe, The Fall of the House of Usher, still leaves the room for the critics to explore. In the study, the niche ecostate-ecorole theory is employed to explain the death of Roderick Usher. On the one hand, his ecostate is poisoned by the unfavorable environment around the House of Usher, and worsened by the lonely living atmosphere, which distorted him both physically and psychologically. On the other hand, his useless ecorole in his living surrounding and demonically burying his twin sister Miss Madeline adversely affected his ecostate. When his ecostate and ecorole was finished, his niche as a natural human ended. It is supposed that the ecolinguistical explanation provides a new angle for the analysis of the death of Roderick Usher.