This paper puts forward an advanced technology of super high-sensitivity helium mass spectrum leak detection by cumulative method. Based on this technology and special processing technics of related materials,the author designed and produced a new type of super high-sensitivity leak detector with detecting sensitivity surpasses 8×10-15 atm.cc/s.He,which is more than 1000 times as that of usual helium mass spectrum leak detectors. This new type of super high-sensitivity detector has been successfully applied in the R&D and producing technics checking of long-life vacuum electrical components like infrared FPA detector.It is also an essential leak rate detection device for super highly-sealed products e.g. energetic particleaccelerator,nuclear physics,aerospace products etc.