The invention belongs to the technical field of medicament, and particularly relates to piperazinone substituted tetracycline derivatives shown in a general formula (I), and pharmaceutically acceptable salts or isomers thereof, wherein R<1a>, R<1b>, R<2>, R<3a>, R<3b>, R<4>, R<5a>, R<5b>, R<6>, R<7>, R<8>, R<9>, R<10>, R<11>, R<12>, R<13>, X and Y are defined in the specification. The invention also relates to a method for preparing the compounds, medicinal composition containing the compounds, as well as application of the compounds in the preparation of medicaments for treating and / or preventing tetracycline sensitive diseases, particularly in the preparation of medicaments for treating infectious diseases.