Writing is an important part of English teaching in senior high school. It is one of the important language skills that students need to master. Under the background of the new curriculum reform, teachers should pay attention to innovative educational ideas, use large unit teaching methods to teach writing skills, provide students with rich writing opportunities, and promote the improvement of students’ writing levels. Based on this, this paper studies English writing teaching strategies from the scientific perspective of large unit teaching, analyzes the value of large unit teaching in English writing teaching, and puts forward specific implementation strategies, aiming to effectively improve students’ English writing level by integrating teaching content, improving students’ writing ability and understanding of the subject.