The present invention belongs to the field of pharmaceutical chemistry, and relates to a substituted pyrrolopyrimidine CDK inhibitor, in particular to a compound as shown in formula I or a pharmaceutically acceptable salt or solvate thereof, as well as a preparation method thereof and a pharmaceutical composition thereof. The present invention also relates to the use of the compound and the pharmaceutical composition thereof in the preparation of a drug for treating diseases associated with CDK inhibition. The compound according to the present invention has a marked inhibitory effect on CDK, excellent drug absorption and significantly superior oral absorption effect.