Abstract: Total Focusing Method (TFM) for ultrasonic phased array imaging is a new technique in ultrasonic detection. It is based on the idea of echo data off-line analysis for post-processing of received signals. Because of its high imaging resolution, wide coverage, high sensitivity to small defects and so on, this technique has been preliminarily applied in the fields of aerospace, high speed railway, oil pipelines, nuclear power plants and others. This paper introduces the detection principle, advantages and disadvantages of the total focusing method for ul-trasonic phased array imaging, summarizes the development situation at home and abroad, and sums up the research hotspots and the development tendency.