Disclosed is a dishwasher (10). The dishwasher (10) comprises a body (101), an air passage (102), catalyst pieces (103) having nanometer titanium dioxide, and an ultraviolet lamp (104) used for emitting ultraviolet light to the catalyst pieces (103). An accommodating cavity (1011) used for accommodating tableware is defined in the body (101). A gas inlet (1012) and a gas outlet (1013) are defined in the wall of the accommodating cavity (1011). An air outlet of the air passage (102) is in communication with the gas inlet (1012), and an air inlet of the air passage (102) is in communication with the gas outlet (1013). The catalyst pieces (103) are disposed in the air passage (102). The ultraviolet lamp (104) is disposed in the air passage (102).