The invention discloses a nasal oxygen cannula with an antibacterial function. The nasal oxygen cannula comprises a main oxygen catheter, an oxygen distributing connector, auxiliary oxygen catheters, a communicating tube and nasal cannulas; each nasal cannula comprises a hollow cylindrical nasal cannula body, an oxygen outlet and an outer ring sleeve, wherein the outer ring sleeve comprises an outer ring sleeve body part and a front end hemispherical part, a gap for facilitating patient breath is formed between the outer ring sleeve body part and the hollow cylindrical nasal cannula body, and breath holes are formed in the front end hemispherical part. The nasal oxygen cannula further comprises an antibacterial component arranged on the main oxygen catheter and comprises a hollow cylindrical shell, a first bacterium-proof film, a second bacterium-proof film and a third bacterium-proof film, and the three bacterium-proof films are sequentially arranged from an oxygen inlet to the oxygen outlet and provided with filtering micropores in different pore diameters respectively. By means of the mode, the nasal oxygen cannula can ensure smooth breath of a patient and will not damage the nasal cavity intima and ensure that input oxygen meets the high-standard sterile sanitary requirements.