The present invention relates to a sodium glucose cotransporter 2 (SGLT2) inhibitor with a phenyl C-glucoside structure, its preparation method, a pharmaceutical composition containing the same, and its use in treating diabetes and preparing an anti-diabetes medicament. The invention provides a compound with the structure of general formula I and a pharmaceutically acceptable salt and prodrug ester thereof,wherein, the definitions of R5 and R6 are selected from the following:(1) R5 = R6 = Me (2) R5 =Me, R6 = OMe (3) R5 =Me, R6 = H (4) R5 =Me, R6 = F (5) R5 = F, R6 = H and (6) R5 = OMe, R6 = H.