Language is the foundation of learning, while writing is the comprehensiveperformance of language ability. Previous studies indicate that students’ observations and feelings towards people and things around them often affect their performance in collecting writing material, and further affect their writing performance.So, to improve students’ writing skills, studentshave to learn how to observe first. Cooperative learning method can enable students to widen their observation scope by discussing and sharing their observing methods and objects; whilemultimedia materials can break the physical limitations of the writing scene, reproduce diverse observation situations, simplify the message, expand students’ sensory experience, and enhance their interest in learning. So the study intended to integratecooperative learning method and multimedia materialsinto the observation teaching forelementary middle-grade students, in hope of enhancing theirwriting material observing ability inwriting. The studyadopted action researchwhich has two stageswitheachlastingsix weeks. Twenty-seven3rd grade studentsfrom an elementary school in New Taipei Citywererecruited. Multimedia teaching materials were developed for the four lessons, which included“human observation”, “objects observation”, “scenes observation”and “things observation” while cooperative learning was integrated into the above four lessons. Qualitative data through observations and interviews, supplemented by some documents like record sheets, feedback questionnaires, and worksheets were collected. Additionally, students’ performance in observation was also evaluated at the beginning and end of the action research. Several findings were discussed. First, students’ observation abilities were enhanced. Second, cooperative learning method enriched interaction among students and encouraged discussion and exchanging ideas during the observation process.Moststudents enjoyedlearningcooperative learning.Multimedia materialscan attract students’interests and attentions.