Compared with the conventional design method based on function, "spatial-form-first" helps designers focus on the study of space form to obtain a more touching spatial experience. However, classroom practices show that the prior spatial form is often weakened in the section of function placement, and even the formal order of the spatial form is gradually dissolved.??This paper enumerates the practical difficulties frequently encountered in the teaching of interior design in terms of functional framework, furniture facilities and human body scale, and puts forward the solution strategy of "elastic function".??The results of the experiment show that this strategy not only solves the contradiction effectively, but also improves the students' spatial design thinking and the ability to solve complex design problems by using graphic method.