The invention belongs to the traditional Chinese medicinal material field, and relates to a Turpinia arguta leaf extract, which contains a flavonoid chemical constituent and acceptable salt in the medicine thereof. The content of total flavonoids is more than 15 percent; the content of apigenin aglycon and a flavone glycoside constituent which uses apigenin as aglycon is no less than 1.5 percent measured in the apigenin; a flavonoid chemical constituent contains one or more of the apigenin, apigenin-7-O-Bata-neohesperidoside, apigenin-7-O-2<1>-Bata-rhamanopyranosyl rutinoside, apigenin-7-O-Bata-glucoside, luteolin-7-O-Bata-glucoside. The invention furhter provides a method for preparing the extract thereof, a method for controlling the quality of the extract, and the application of the extract for preparing the medicines such as antibiosis, oxidation resistance, anti-mutation, antitumor, hepatic protection, anti-hepatitis b virus, anti-thrombosis, anti-arteriosclerosis, etc.