The paper reports a new method of preparing dye image diazonium salt sensitive paper with 3-methoxydiphenylamine-4-diazonium salt and coupling agent. All the indices such as the speed of sensitization, intelligibility, contrast and conservation property of the prepared paper meet the same level of Japanese Ricoh high speed diazo paper SDE. The paper also expounds the exposure, development and image formation principles and methods of diazo sensitive paper and the methods for quality detection.