Abstract: The micro leakage often appears during pressure test of vessels equipment with titanium/steel and zirconium/steel cladding plate because of the tiny defect of the weld of the cover plate. However, the common practice single NDT method is not easy to detect or accurately position the defect. Through demonstration of three kinds of combination detection process, the results show that the helium leak detection-fluorescent penetrant method, as well as the ammonia leak detection-fluorescent penetrant method can realize accurate positioning of micro leakage point, and solve the problem of micro leakage detection.