Pressure equipment,as the key equipment of the large complete equipments such as ten million tons refinery,one million tons of ethylene and supercritical(ultra-supercritical)power plant boiler,its uniform wall thinning which caused by corrosion could be on-line assessed by pulsed eddy current(PEC) testing technology. It has important significance to ensure the long cycle operation of the large complete equipments. The background of studying the PEC testing technology for pressure equipment is introduced,and the advantage of on-line assessment by the technology is pointed out. After the PEC testing principle and the PEC signal characteristics of steel have been researched,the works on PEC testing theory for realizing and optimizing the testing function are introduced. The characteristics and applicable conditions of PEC testing are proposed when the influence mechanism of the factors met in the field is investigated. The first national,energy and international standards,which are continually established based on the above researches and considering the actual requirements,as well as the self-developed instrument,are introduced. Two typical field applications are presented,to illustrate the practicability and reliability of PEC testing technology in assessing the wall thinning of pressure equipment.