Disclosed is a compound of formula I, or a pharmaceutically acceptable salt, solvate, polymorph, enantiomer or racemic mixture thereof, wherein R1 and R2 are each independently hydrogen, -OH, alkyl, -CF 3 , -OCHF 2 , -OCF 3 or halogen； R3 is cycloalkyl, -OCH 2 CF 3 , -OCH 2 CHF 2 , -OCH 2 CH 2 F or -OCH 2 CH 3 ； R4 is hydrogen, -OH, -O aryl, -OCH 2 aryl, alkyl, cycloalkyl, -CF 3 , -OCHF 2 , -OCF 3 , -OCH 2 CF 3 , -OCH 2 CHF 2 , -OCH 2 CH 2 F or halogen； A is -CX 1 X 2 , wherein X 1 and X 2 are each independently H, F and Cl, and when both X 1 and X 2 are H, R3 is not -OCH 2 CH 3 . The compound has an activity of inhibitors of sodium-dependent glucose transport protein. Also disclosed is a method for preparing the compound, a pharmaceutical composition comprising the compound, use of the compound and pharmaceutical composition thereof in preparing medicaments of SGLT2 inhibitors and treating related diseases.
