The invention belongs to the fields of medicament and chemical industry, and discloses a carbazole derivative, a preparation method of the carbazole derivative, and an application of the carbazole derivative serving as an anticancer drug. The structural formula of the carbazole derivative is shown in the specification, wherein R1 is piperidyl, morpholinyl, piperazinyl or Bielin group; n is 1, 2 or 3; and R2 is pyrazolyl or pyridyl. At the same time, the invention discloses a preparation method of the carbazole derivative and an application of the carbazole derivative serving as the anticancer drug. The carbazole derivative has strong inhibiting action on the expression of telomere DNA (deoxyribonucleic acid) and DNA of c-myc and other proto-oncogene, has significant inhibiting action on multiple cancer cell strains, has low toxicity to normal cells, and has broad application space in preparation of anticancer drugs.