A novel concept to estimate the shape of inner hole in course of honing is presented in this paper. Based on analysis of machining condition, five sections measuring model is established in process pneumatic measurement system for inner hole honing. It used matrix algorithms to simplify judging process about inner hole shape. And it improves the accuracy of machining area in inner hole. The method and principle are elaborated in this article. Program module was designed and written for experiment. And the experimental data show that the measuring model is feasible.