Abstract: The convex phased array probe was adopted in this paper for performing internal inspection of the tubular equipment. According to the structure characteristics of two layer medium, the paper theoretically analyzed the focusing performance of phased array acoustic field. Based on the model of near field spherical beam forming, the delay time can be obtained by the route of acoustic beam which can be used as stimulation time for each array elements. Phased array focusing law of the water-steel two layer medium is designed in this paper. The simulation on the phased array acoustic field with CIVA software is completed to determine the phased array probe parameters, including array elements, array element size, ultrasonic frequency and so on. At last,the double layer circular ring probe of 512 array elements is manufactured according to the phased array parameters which have been optimized,the test on tubular samples which contain artificial flaws is performed. Experiments indicate that this technique can detect the corrosion and the porosity flaw,with high sensitivity and efficiency. The corrosion and embedded flaws of the tubular equipment can be detected by internal inspection.