Disclosed in the present invention are a pyrimidone compound represented by formula (I), a pharmaceutically acceptable salt thereof, or a solvate thereof. Also provided in the present invention are a preparation method for the pyrimidone compound, a composition comprising the pyrimidone compound, and a use of the pyrimidone compound in the preparation of a drug for treating diseases or disorders associated with the mechanism of action of an EED protein and/or a PRC2 protein complex.