In this study, a genre type, narrative, from the frameworks of genre in the Australian primary classroom, was used to design summary and story writing instruction. The participants of the study were a class of 30 fourth graders in an elementary school of Taiwan. The students written works were analyzed and writing behaviors were observed for measuring students writing performance, while pre- and post-instruction questionnaires were conducted to report their affective aspects. The results showed that most students could write story summaries and create their stories after the genre- based writing instruction. The majority of them also reported positive views towards English writing. The results of the study implied that formal correctness should not be a major criterion for judging students writing performance because it has little connection with students meaningful communication. Teachers should adopt a more flexible writing approach to suit students needs and interest. Thepurpose of writing is to help students become less inhibited about communicating in English so that they can express themselves in meaningful contexts.