Abstract: MS ahead fluid is composed of micromolecule polymer,surfare activity agent,shale stability agent, micro silicon and weighting material. MS have three flush actives: hydralical, mechanical and chemical. It can isolate the slurry from drilling fluid improving displacement efficiency of cement.Because of its small API filtration rate and filming function,MS can reduce filltration of slurry entering formation to avoid payzone dameged. MS is applied in 10 wells in which cement qualification rate achieve 100% and high cement quality rate is over 95% in sections in northeast Tarim,Xinjiang.