The present invention discloses a class of carboxylic acid derivatives and use thereof in preparation of prodrugs. The carboxylic acid derivatives have the general formula (I), wherein R 1 is H or alkyl; X is H or F; Y is F or fluoroalkyl; n is 0, 1, 2, 3, 4, 5, or 6; W is W 1 or W 2 ; W 1 is NR 2 R 3 NR 2 R 3 ·A, R 2 and R 3 are each independently H, alkyl, cycloalkyl, or a protecting group for amino; m is 0, 1, 2, or 3; A is an acid; W 2 is COOR 4 , OPO(OR 4 ) 2 , or PO(OR 4 ) 2 ; R 4 is H, or a protecting group for carboxyl or hydroxyl in phosphoric acid.