Diagnosis method for thallium poisoning of SCR denitration catalyst

The invention relates to a diagnosis method for thallium poisoning of an SCR (Selective Catalytic Reduction) denitration catalyst, which comprises the following steps that: a sample catalyst is selected, and in a field environment, the consumption of a reducing agent of an SCR reactor is increased by more than 15%; under a laboratory condition, it is measured that the activity of the sample catalyst is reduced by more than 15%; and when a first condition and a second condition are met at the same time, the content, the specific surface area, the acid site number and the strength of sulfur, potassium, calcium and thallium elements in the sample catalyst are tested, and finally thallium poisoning of the catalyst is judged. According to the method, abnormal inactivation caused by thallium poisoning of the catalyst can be accurately judged, so that the catalyst can be regenerated in a targeted manner, and the conditions that the emission of a single compound does not reach the standard and the regeneration succes