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 R1 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 W1 or W2; W1 is NR2R3, NR2R3.A, R2 and R3 are each independently H, alkyl, cycloalkyl, or a protecting group for amino; m is 0, 1, 2, or 3; A is an acid; W2 is COOR4, OPO(OR4)2, or PO(OR)2; R4 is H, or a protecting group for carboxyl or hydroxyl in phosphoric acid.