Abstract: The reactor pool of nuclear power plants generally adopts stainless steel cladding structure, leakage occurred during construction and operation. Based on the characteristics of cladding structures, experimental investigation of the array eddy current inspection of cladding weld was carried out. The detectability of manual groove and hole defects in plane butt weld was mainly investigated. The results verify the feasibility of using array eddy current to detect weld defects in reactor pool. Through the array eddy current inspection of the reactor pool weld during the in-service inspection of a power plant, its characteristics and some problems encountered are summarized, which can provide reference suggestions for the leak detection of the pool during the in-service inspection of nuclear power plant.