Abstract: The paper describes the inspection principle of soft X-ray machine having a Be-window and a fine focal spot of 0.4×0.4mm.The performances of some types of films home-made have been compared with those made in other countries.And it also introduces the selections of the suitable radiographying para meters,including the exposure-chart and the relative curve between the material thickness under inspected and the film-densities used,and the types of defects that can be found.Using penetrant enhanced X-ray radiography,the delamtnations around the holes drilled in CFRP are detected.