Cannabinoid extraction and purification method

The invention discloses a cannabinoid extraction and purification method. The method comprises the following steps: 1, taking and crushing a dried hemp raw material to obtain hemp powder; 2, adding the hemp powder into subcritical extraction equipment, then pumping a subcritical acetic acid aqueous solution in an amount which is 5-10 times that of the hemp powder, and circularly extracting to obtain a hemp extract solution, wherein the subcritical acetic acid aqueous solution is prepared by pretreating an acetic acid aqueous solution to a subcritical state with the temperature of 250-350 DEG C and the pressure of 5-25 MPa, and the pH value is 3-5; 3, cooling the hemp extract solution to 70 DEG C or below, and centrifuging to remove a medicine residue layer and a water layer, so as to obtain a crude oil extract; 4, carrying out molecular distillation purification and impurity removal to obtain hemp full-spectrum oil; and 5, purifing: carrying out gradient elution by using a chromatographic column, and collecti