An axle oil composition having enhanced fuel efficiency and low viscosity is provided, wherein the axle oil composition contains 40 to 70 wt % of poly alpha olefin (PAO) synthetic oil; 5 to 35 wt % of an oil soluble poly alkylene glycol (OSP) synthetic oil; 15 to 20 wt % of an ester-based viscosity modifier; 0.05 to 0.5 wt % of calcite; and 5 to 20 wt % of additive, wherein the axle oil composition having enhanced fuel efficiency and low viscosity has average kinematic viscosity at 100° C. of 11.5 to 13.5 cSt and average kinematic viscosity at 40° C. of 65 to 75 cSt and forms an oil film having a thickness of 85 to 96 nm even at low viscosity, largely improving durability and fuel efficiency of a vehicle.