The experimental teaching in vocational school is the efficient avenue to enhance the students' quality of experiment and ability of scientific research and train their creativity. At a certain extent, CAI experiments can make up for such shortcomings of traditional experimental classes as lack of cost, long procedure and some ones unrealized. And the simulation experiments by computer in experimental teaching are the counterpart of the real ones. The advantages, types, design methods and defects are introduced in this thesis beginning with analysis of the types of multi-media in experimental class, and the methods and steps to make CAI are emphasized on. The hope is to draw lessons for other experimental classes in vocational school to make CAI and stimulate the interest and creativity of the students, so the teaching quality will be enhanced in vocational school.