The diamond model is introduced into patent analysis to analyze the competition situation of patents for esophageal cancer study in six terms of production factors, requirements, related and supportive industries, enterprises' strategic structure and industrial competition, opportunities and governments based on literature on patents for esophageal cancer study collected by patent retrieval system of State Intellectual Property Office(SIPO) since 1985, in the hope of serving as references for the research and development of esophageal cancer technologies.