The method of extracting biological active substance from eucommia leaf as raw material includes the following processes: 1. using water, methyl alcohol or ethyl alcohol as extracting agent and adopting the procedures of ultrasonic vibration extraction or heating extractino, macroporous resin adsorption and ethyl alcohol elution, etc. to extract eucommia total glyciside and total flavone; 2. using water, methyl alcohol or ethyl alcohol as extracting agent, and adopting the procedures of macroporous resin separation, ethyl acetate extraction and mixed solvent recrystallization to extract chlorogenic acid and eucommia flavone; and 3. using acid aqueous solution as extracting agent, and adopting the procedures of macroporous resin separation, active carbon decolouring and ethyl alcohol precipitation to extract eucommia acid polysaccharide from eucommia leaf residue after other active components are extracted.