The invention provides an indole pyrimidine type marine alkaloid Meridianin G derivative as well as a preparation method and application thereof. According to the invention, the Meridianin G derivative with antitumor activity is obtained by introducing a substituent having an end of a saturated aliphatic chain connected with different pharmaceutical groups to an indole N-site on the basis of retaining an indole pyrimidine mother nucleus according to structural characteristics of a marine natural product Meridianin G alkaloid, and aromatizing 2'-site of a pyrimidine ring, wherein the MeridianinG derivative has a structural formula as follows: (FORMULA). Activity of a compound at a cellular level is tested in the invention; experiments of the invention prove that the Meridianin G derivativeprovided in the invention has relatively strong anti-tumor activity at the cellular level, can be used for preparing anti-tumor medicines and has good market application prospects.