The invention discloses a universal inflating valve assembly of an inflator. The universal inflating valve assembly comprises a main body, a mandrel and an inflating valve head in thread connection with an American tire valve and a French tire valve, wherein the inflating valve head is nested on the main body in a sealed manner and can rotate by 360 degrees relative to the main body, the rear end of the main body is fixedly connected with an air pipe, the mandrel is arranged in the main body, and the front end of the mandrel penetrates through the inflating valve head. The universal inflating valve assembly is characterized in that a primary steel ball tightening mechanism used for realizing switching of the American tire valve and the French tire valve is arranged among the mandrel, the main body and the inflating valve head, and a secondary steel ball tightening mechanism used for realizing switching of the American tire valve and the French tire valve is arranged between the main body and the inflating valve head. The universal inflating valve assembly has the advantages that the universal inflating valve assembly is simple in structure and simple and convenient to operate; when American and French use modes of the universal inflating valve assembly are required to be switched, all that is required is to slide a sliding sleeve forwards and backwards, and the current American or French use mode of the universal inflating valve assembly can be directly identified by naked eyes according to the front-and-back position of the sliding sleeve.