Abstract: The sample-tilting X-ray diffraction (STD) technique was performed on the conventional X-ray diffractometer in this paper. Using this technique, structure of thin film can be detected without special film attachment (TFA). Authors also developed a diffraction intensity equation and an azimuth equation, which can theoritically character the habove technique. This method has been successfully used for solving some pro- blems of structure, which were unsolved by other simple methods such as longitudinal distributions of phases. The features of this technique were demonstrated with some application examples and came to the following conclusions: a. The application of STD technique has extended the function of X-ray diffraction. b. The STD technique is suitable for detection of phase structure of thin film materials. c. The measurement of longitudinal distribution change of the phase structure can be performed by using STD technique.