The invention belongs to the field of medicinal chemistry, and relates to a class of isonicotinic acid derivatives with novel structures, a preparation method and application thereof. The present invention mainly relates to isonicotinic acid derivatives represented by formula (I), stereoisomers, racemates, tautomers, or pharmaceutically acceptable salts thereof, and preparation methods thereof and in the preparation of anticancer Uses in medicine. In formula (I): Z is selected from O, S, NR 3 , where R 3 for hydrogen or C 1 ~C 6 the alkyl group; R 1 from C 1 ~C 6 Alkyl, C 1 ~C 6 Alkoxy, halo C 1 ~C 6 Alkyl, aryl, aryloxy, heteroaryl, heteroaryloxy, heterocyclyl, heterocyclyloxy, halogen; R 2 selected from halogen, cyano, nitro, C 1 ~C 6 Alkyl, C 1 ~C 6 Alkoxy or halo C 1 ~C 6 Alkyl; m is an integer of 0-4; n is an integer of 0-5; with the proviso that Z is selected from NR 3 , when m is 0 and n is 1, R 2 Not halogen.