The effect of nano-calcium carbonate particles as additives on the titanium complex grease was investigated in this paper. Tribological properties of the titanium complex grease containing nano-calcium carbonate were evaluated with a four-ball tester. The morphology of wear scar of steel ball was observed using the sweep electron microscope. The chemical states of typical elements on the wear scars of steel balls were analyzed by means of the X-ray photoelectron spectroscopy. The results showed that the titanium complex grease including 3% or 5% nano- calcium carbonate has better antifriction and antiwear properties. The nano-calcium carbonate particles through generating calcium oxide and adsorption to form a protective film effectively inhibited the adhesive wear and contact fatigue of the friction surface to reduce wear.