The present invention relates to 9-aminomethyl substituted tetracycline compounds represented by formula (I), or pharmaceutically acceptable salt, prodrug, solvate or isomer thereof, as well as a method for preparing these compounds and a pharmaceutical composition comprising the same. The present invention relates also to a use of these compounds in the preparation of a medicament for the treatment and/or prophylaxis of tetracycline drug-sensitive disease. wherein, R 2a , R 2b , R 3 , R 4a , R 4b , R 5 , R 6a , R 6b , R 7 , R 8 , R 9a , R 9b , R 10 , R 11 , R 12 , R 13a and R 13b are each independently as defined in the description.