Avermectin and preparation method thereof

The invention discloses avermectin and its preparation method. The preparation method comprises the following steps: 1) degassing toluene and heating to 40-50 DEG C and adding an avermectin crude extract to prepare a mixture M1; 2) heating the mixture M1 to 70-80 DEG C, and stirring the mixture M1; 3) standing and taking a supernatant from the mixture M1, cooling to 15-20 DEG C, filtering and taking a crystal substance M2; 4) degassing acetone and heating to 25-35 DEG C and adding the crystal substance M2 so as to obtain a mixture M3; 5) heating the mixture M3 to 50-60 DEG C, and stirring the mixture M3; 6) standing and taking a supernatant from the mixture M3, cooling to 15-20 DEG C, filtering and taking a crystal substance M4; and 7) cleaning the crystal substance M4 with water, filtering and drying to obtain avermectin. Through the above mode, avermectin with high concentration is obtained. According to the invention, using effect of avermectin is greatly enhanced, and pesticide effect of avermectin is increased.