Abstract: In view of the structure and weld characteristics of tubular equipment such as tube to tube-sheet fillet weld, pipe seat fillet weld, gas storage well,etc., the probe can reach into the inner wall of pipe to detect the defects with high detection rate. In this paper, an ultrasonic phased array detection technique is proposed to realize the in-tube detection of tubular equipment. The acoustic field model of planar and convex phased array is introduced. By using CIVA simulation, the characteristics and applicable range of several different detection methods such as 1D linear array, convex array and flexible phased array are compared. It can provide reference for extending the application of phased array technique in the inner detection of tubular equipment.