The invention belongs to the field of drug synthesis, and discloses a 4-methoxyl-5-hydroxy canthinone ramification. The compound structure of the 4-methoxyl-5-hydroxy canthinone ramification is as shown in a formula I described in the specification, wherein A is selected from C2-8 alkyl or -(CH2)n-, and n=2,3,4 or 5; B is selected from halogen, 3-9 element heterocyclic radical and -NHR1 or -NR2R3, wherein the 3-9 element heterocyclic radical contains one or more N atoms; R1, R2 and R3 are same or different and are independently selected from C1-6 alkyl. The invention also discloses a preparation method of the 4-methoxyl-5-hydroxy canthinone ramification and an application of the 4-methoxyl-5-hydroxy canthinone ramification in preparing antitumor drugs. The preparation method disclosed by the invention provides a series of 4-methoxyl-5-hydroxy canthinone ramifications by carrying out structural modification on the 5-hydroxy of 4-methoxyl-5-hydroxy canthinone and provides an idea for further screening the antitumor drugs.