The development of cost-effective In2O3-based sensors exhibiting high sensitivity and selectivity to NO2 at low temperature is still a challenge. For the first time, Sb2O3 modified porous In2O3 hexagonal nanotubes (Sb2O3/In2O3 HNTs) have been synthesized for highly efficient NO2 sensing. Texture characterizations indicate that Sb2O3/In2O3 HNTs with ultrathin wall thickness of ca. 20 nm and big inner diameter of ca. 500 nm displays high specific surface area of 100.3 m(2).g(-1). Gas sensing property tests display that In2O3 HNTs with Sb2O3 loading of 1.5 mol% exhibit high response (R-g/R-a= 47), superior selectivity and short response/recovery time (80/85 s) to 1 ppm NO2 in comparison with reported other sensing-materials at 80 degrees C, and the detection limit of Sb2O3/In2O3 HNTs toward to NO2 is down to 50 ppb (S= 2). The mechanism investigations reveal that the hetero-junction at Sb2O3/In2O3 interfaces, catalytic function of Sb2O3, and high specific surface area result in the high response, superior sensitivity, and short response/recovery time of Sb2O3/In2O3 HNTs sensors at low temperature. Therefore, this work provides a promising candidate for the development of high-performance sensor to NO2 gas at low temperature.