The description of pressure equipment accidents has always been expressed in large paragraphs. It was difficult for readers to grasp the contents of the whole accident and analyze the objective laws of the accident. The representation method based on chart can show the accident context of pressure equipment intuitively and clearly, so that readers can quickly grasp the causes and consequences and development law of the accident. In this paper, the research framework of pressure equipment accident characterization method was established. Three characterization methods: fault tree, fishbone diagram and radar chart were used to analyze a typical pressure equipment accident. The advantages and disadvantages and application scope of the three characterization methods were obtained by comparing the analysis process and results. The results show that fault tree and fishbone diagram can not represent the weight of each factor, but radar chart method can do it directly. Radar chart method is suitable to analyze the primary and secondary causes of pressure equipment accidents. Since the radar chart has never been used in the accident analysis of pressure equipment before, a new characterization method of pressure equipment accident was established based on radar chart in this paper.