Using layered α-Zr(HPO4)2·H2O（α-ZrP）as the precursor,Na-α-ZrP solid sample was prepared by hydrothermal synthesis,and the crystal structure and morphology were characterized by Xray diffractometer and scanning electron microscope.Calciumbased grease with additive Na-α-ZrP was prepared,the effect of Na-α-ZrP on the rheological properties and tribological properties of calciumbased grease was studied by using a rheometer and a fourball tester,and the surface morphology,chemical element distribution,and chemical state of scar wear were analyzed with 3D optical profiler,scanning electron microscope,Xray spectrometer,and Xray photoelectron spectroscopy.The results show that Na-α-ZrP has a good crystallinity and a lamellar structure,which can significantly improve the viscoelasticity and viscositytemperature properties of the base grease.Na-α-ZrP as a solid additive enhances extreme pressure properties of base grease.Under different loads,speeds and times,Na-α-ZrP exhibits excellent friction reducing and antiwear performance.It is found by analysis of the chemical element distribution and chemical statethe of the wear surface that Na-α-ZrP forms a solid protective film formed by Na,Zr,P,and O elements on the friction pair during the friction.