The invention relates to magnolola derivatives, the preparation method thereof, medical compounds with the magnolola derivatives as active components, as well as the application of the medical compounds in cancer treatment, pertaining to the technical field of pharmaceutical chemistry. The magnolola derivatives of the invention mainly include 3-substituted derivatives of magnolola; wherein the magnolola derivative with the formula I a is an intermediate product; the structural formula of the magnolola derivatives is II, wherein R1 is one of the following: H, halogen, hydroxyl, cyano, nitryl, amidocyanogen, alkyl, halogenated alkyl, cyanogens alkyl, hydroxide alkyl, allyl, amide, alkyloxyacyl, alkoxy, thiol group, alkyl, phenyl or heterocyclic radical. Cell poison tests and anti-tumor cell tests show that the magnolola derivatives have good anti-tumor effects.