In order to study the influence of calcium carbonate whisker with different content on the mechanical properties and microstructure of polyethylene fiber reinforced cement-based composite(PE-ECC),four groups of PE-ECC specimens with different content of calcium carbonate whisker were designed,and the compressive properties,tensile properties and three-point bending fracture properties were tested on them.The microstructure was studied by XRD,SEM and NMR.The results show that calcium carbonate whisker can strengthen and toughen PE-ECC.With the increase of calcium carbonate whisker content,the strengthening and toughening effects first increase and then decrease.When the content of calcium carbonate whisker is 1%(volume fraction),the compressive properties,tensile properties and fracture properties of PE-ECC are improved best.Appropriate amount of calcium carbonate whisker can fill the matrix,reduce the number of less and more damaged pores,and improve pore structure.