Thesis is divided into three parts. The first part introduces the task based-layer teaching five steps instructional design of English Business Correspondence in Business School of the Vocational Technology. The five-step design develops on the basis of traditional pre task, task and review, the tree-step teaching model, taking into account of the poor English of students in Vocational school, we add preparing lessons before class and exercising to consolidate after class the two rings. So the five-step is preview before class - pre task: the situation creation, case introduction, leads to the task - task: discuss a writing program, task decomposition, first attempt to writing step by step, later attempt to writing comprehensively - after task: Showing, evaluation and learning model essay, self correction, after class: practicing, consolidating and improving. This design not only embodies the characteristics of task-based teaching, also shows the ideas and methods of hierarchical interactive teaching. In the second part of the paper, it gives the specific design of each step e of the task based-layer teaching in detail, taking the example of how to write the letter of amendment to the L/C, which clearly tells us how to carry out the whole process of five -step teaching. The third part introduces the writer's reflection of implementation of the task based-layer teaching five steps instructional design.
