Abstract: As an advanced nondestructive testing technology, the application of industrial CT has become increasingly widespread. There are hundreds of industrial CT systems currently in use. If the industrial CT hardware equipment is different, the corresponding process parameters are also very different. Although the current industrial CT standards in the main process parameters provide guide lines for selection principles, they do not give a quantitative selection method and hence the operation is inconvenient. Based on the sampling theory, this paper gives the formula of the main parameters, which greatly facilitates the preparation of the CT detection process. The operation procedure is given by examples and the correctness of the method is verified.