Abstract Special review of element compounds in senior three should pay attention to the promotion of students' inquiry consciousness and the establishment of the thinking framework of situational inquiry. In inquiry activity design of element compounds, this paper integrated the process of substance transformation of iodine and its compounds and the reasons for "abnormal phenomena" in the reaction, carried out the teaching around how to design the experimental scheme to carry out empirical activities, how to collect evidence to prove or disprove the conjecture. This paper expounded thoughts and implementation methods of inquiry activity design, and formed the general thinking model of solving the problem, and made teaching reflections.