The invention relates to the technical field of glass edge covering, in particular to a glass edge covering assembly and an injection molding method thereof. The injection molding method is characterized by comprising the following steps that an upper mold and a lower mold which are used in pair are provided; a bright plastic decorative plate is placed and positioned in an insert cavity, and the outer surface of the bright plastic decorative plate is attached to the bottom surface of the insert cavity; glass is placed on a supporting mechanism and positioned through a positioning mechanism; the upper mold and the lower mold are assembled, so that an injection molding cavity is formed between the bright plastic decorative plate and the glass, at least one edge of the glass is located in theinjection molding cavity, and a sprue of the injection molding cavity is arranged right opposite to the inner surface of the bright plastic decorative plate; and plasticized thermoplastic resin is poured into the injection molding cavity through the spure, and the glass edge covering assembly is manufactured after cooling molding. The injection molding method has the advantages that positioning is accurate, the injection molding quality is high, and the appearance is good.