Abstract The impact of changing Japanese language instruction in higher education institutions on students’ intercultural communication skills is examined in this paper using gray correlation. To create the gray correlation value matrix of the ideal response, a comparison study of the geometric relationships between the system data series and the geometry of the curves is done. The set of signals for the ideal response and the negative one is established by examining the specific steps of the ideal response approach. The multiplicative synthesis method was used to assign weights to the combinations of decision indicators, and the assignment formula was calculated. The results showed that 42% of the students wanted to learn everyday Japanese in Japanese language teaching, only 21% wanted to learn professional Japanese and industrial Japanese, and most of the learners preferred to improve their communicative ability through Japanese language teaching courses. The most desirable communicative ability of students should be 43% of expression and imagination.