Essays in different text genres have different ideas and writing method. Prediction the text genres firstly will help get a better accuracy when predicting the success of literary or finding the beautiful words and sentences in the essay. And it will help set a different standard for different text genres when scoring the writing by computer. Words and structure can be effective in discriminating text genres. Narration and description has a difference in the words they use and the structure, we can separate them by analyze the difference. In this paper we find a method to separate the essay in different text genres by computer. We analyze the most effective features for distinguish genres. And discussed how to get a better result for genres classification. Finally, the f value reached 80% in our experiment.