The invention belongs to the field of molecular biology and mainly relates to a universal kit and method for extracting DNA from trace plant materials. The yield of DNA extracted once through the kit and the method can completely meet the requirement of direct whole genome sequencing. The kit and the method mainly comprise a thin silicon matrix adsorption column capable of adsorbing genome DNA to the maximum extent and a unique extraction buffering liquid system which is matched with the silicone matrix adsorption column and can extract various plant tissues and DNA in different parts of plants to the maximum extent. The kit and the method have the advantages of rapidness, convenience, no need of phenol-chloroform extraction, avoidance of organic solvent pollution and the like, and pigments, grease and other impurities in the DNA extraction process can be simply and conveniently removed to the maximum extent due to the thin adsorption column. Valuable plant samples are saved, and pretreatment steps and time of whole genome sequencing are greatly reduced and shortened.