The invention discloses an intelligent adjusting method and device for an air purifier and the air purifier. The intelligent adjusting method for the air purifier comprises the steps that 1, the current air quality of an air inlet is detected, and matching between the current air quality of the air inlet and air quality levels is conducted; 2, a current purifying performance level is obtained, and whether the current purifying performance level is matched with a target purifying performance level of the current air quality of the air inlet or not is judged, wherein the target purifying performance level corresponds to the air quality level matched with the current air quality of the air inlet; 3, if the current purifying performance level is not matched with the target purifying performance level of the current air quality of the air inlet, the current purifying level is adjusted to be matched with the target purifying performance level. According to the intelligent adjusting method for the air purifier, the problem that in the prior art, the problem that air can not be rapidly and intelligently purified according to air quality can be solved.