Abstract: The traditionalgas leak detecting m ethods alw ays adopt single m ethod or M S/ G Ctechnique. The instrum ents are bulky and it's difficultto operate them . With therapid developm ent of m odern industry, m onitors w ith sm all size and lightw eight are ingreatneed. In addition,the m onitors m usthave high sensitivity,strong differentiate abilityand excellent security. Com bined the m ass spectrom eter and sensitive thin film together,m anufacture and perform ance is discussed experim entofthe portable gas leak m onitor. Itsapplications in spaceflightare introduced also.