Photocatalyst of N-doped Bi₂O₂CO₃ (N-BOC)/CdSe quantun dots (QDs) composite was sucessfully prepared for degradation of nitric oxide (NO), an indoor air pollutant. The results of X-ray diffraction, transmisssion electron microscopy and X-ray photoelectron spectroscopy showed that after combination with CdSe QDs structure and morphology of N-BOC remained the same as before combination. Photocatalytic degradation of NO showed that introduction of CdSe QDs significantly enhanced the removal ratio of NO. Moreover, the generating ratio of toxic byproduct NO₂ decreased to 1%, which indicated efficient inhibition for the toxic byproduct generation. From UV-Vis absorption spectroscopy and photoluminescence spectroscopy, the CdSe QDs showed promotion on light absorption, and inhibition of charged recombination of photo-induced carriers. More importantly, only signals of NO₃^- were captured in in situ DRIFTS measurements, whilst the signals from NO₂ could be barely detected during photocatalytic process. Superoxide radicals (O₂^-) and holes (h ⁺) are considered to be possible active species in the reaction, which dominate the oxidation process from NO to NO₃^-.