Abstract: In cementing operation,in order to improve cementa- tion between cement mantle and formation,casing,realize well isolation between effective interlamination,ensure well production and sequel well stimulation and prolong the length of well life,performances of cement slurry should be improved.Adding JFR activating fiber into mi- crodilatancy cement slurry system,microdilatancy fiber cement slurry is developed.Through testing on thickening time,rheological property,API fluid loss,cement fold and compressive resistance,cement attenuation resistance of microdilatancy fiber cement slurry,it is found that the thickening time of microdilatancy fiber cement slurry can be freely regulated,rheological property is good,API flu- id loss is low and the performances of cement fold-resist- ance,compressive resistance,attenuation resistance and constriction resistance are very good.