The effects of thermoplastic polyurethane elastomer (TPUE) on mechanical,energy and combustion performance of triethylene glycol dinatrate (TEGN) propellants were studied. Results show that TPUE improves the mechanical properties,especially the impact resistance at low temperature (-40 ℃). When TPUE content is about 1%-3%,the impact strength at -40 ℃ increases by more than 60%. With the increase of TPUE,the propellant force (f) decreases gradually,and the co-volume (α) and pressure exponent (n) increase a little. When TPUE is 3%，f,α and n is changed to 2%,1.4% and 5.3% respectively.