LiNO3 is selected as the additive to modify the electrolyte for lithium sulfur battery. The cycling efficiency (EFF) shows that LiNO3 additive is favorable for the lithium deposition and dissolution on the Cu foil. SEM and XPS are applied to analyze the surface changes of the lithium cycled in the electrolytes. The LiNO3 additive is conducive for the construction of protective film on the surface of the lithium anode. Lithium sulfur batteries are also cycled with the 0.4M LiNO3 modified electrolyte. The lithium sulfur battery tested shows improved cycling performance with the coulombic efficiency above 95% and highly stable reversible discharge capacity of ca. 527mAhg−1 after 50 cycles.