The present invention relates to tetracycline compound, its pharmaceutically acceptable salt, solvate or its isomers that 9- amino methyl shown in logical formula (I) replaces, and wherein R2a, R2b, R3, R4a, R4b, R5, R6a, R6b, R7, R8, R9a, R9b, R10, R11, R12, R13a, R13b are defined as in the description； The invention further relates to the preparation methods of these compounds, the application containing the pharmaceutical composition of these compounds and these compounds in the drug of preparation treatment and/or the prevention disease sensitive to Tetracyclines.本發明涉及通式(I)所示的9-氨基甲基取代的四環素類化合物、其藥學上可接受的鹽、溶劑化物或其異構體，其中R2a、R2b、R3、R4a、R4b、R5、R6a、R6b、R7、R8、R9a、R9b、R10、R11、R12、R13a、R13b如說明書中所定義；本發明還涉及這些化合物的製備方法，含有這些化合物的藥物組合物，以及這些化合物在製備治療和／或預防對四環素類敏感的疾病的藥物中的應用。
