Here in this paper, we report a room-temperature operating infrared photodetector based on the interband transition of an InAsSb/GaSb quantum well. The interband transition energy of 5-nm thick InAs0.91Sb0.09 embedded in the GaSb barrier is calculated to be 0.53 eV (2.35 μm), which makes the absorption range of InAsSb cover an entire range from short-wavelength infrared to long-wavelength infrared spectrum. The fabricated photodetector exhibits a narrow response range from 2.0 μm to 2.3 μm with a peak around 2.1 μm at 300 K. The peak responsivity is 0.4 A/W under?500-mV applied bias voltage, corresponding to a peak quantum efficiency of 23.8％in the case without any anti-reflection coating. At 300 K, the photodetector exhibits a dark current density of 6.05×10?3 A/cm2 under?400-mV applied bias voltage and 3.25×10?5 A/cm2 under zero, separately. The peak detectivity is 6.91×1010 cm·Hz1/2/W under zero bias voltage at 300 K.