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.