Epigenetic modifications mainly include DNA, RNA and histone modifications. The modifications include various forms, including methylation, acetylation, lactylation, and glycosylation, etc. Epigenetic modifications play an important role in the occurrence and development of tumors, which could be applied to the early diagnosis and prognosis evaluation of tumors, and could also prompt a new direction for the targeted therapy strategy of tumors. Traditional Chinese Medicine could play an anti-tumor role by regulating epigenetic modifications. Epigenetic antitumor drugs mainly include DNMT inhibitors, HDAC inhibitors and IDH inhibitors, which have been applied in clinical trials. The research on RNA methylation is still in its infancy and there are no approved drugs, but its important function in tumors has been confirmed. Therefore, DNA, RNA and histone modification could be used as diagnostic or prognostic markers for tumors, and the development of anti-tumor drugs targeting DNA, RNA and histone modification enzymes will become a new direction for tumor treatment.