Abstract: It is described that total mass loss(TML)、collected vo-latile condensable materials(CVCM)and water vapor regained(WVR)are three closely related indexes which reflect outgassing state of spacematerials and provide basic infomation about the tolerance of the ma-terials in space thermo-vacuum environment and the contamination onthe sensitive surface of the spacecraft caused by outgassing.ASTM(TheAmerican Society for Testing and Materials)E595-90 standard,whichis adapted to batch testing,high data reliability,quick testing rateand low cost,becomes the sole standard for screening space materialsby outgassing,and is adopted by all space organizations all over theworld.In view of this,we have formulated an equivalent standard ofthe Ministry of Space Industry QJ 1558-88,and have developed the cor-responding testing deviee,Micro-VCM,which has met allof the require-ments of the ASTM E595-90 standard and and is even better in someaspects,such as temperature control accuracy,balance sensitivity andcontrol of cross-contamination.