The invention discloses 14 3H-imidazo[4,5-c]pyridine-6-formyl-amido acid benzyl esters shown in the general formula I. In the general formula I, AA represents L-Ser residue, L-Glu (OBzl) residue, L-Phe residue, L-Val residue, L-Arg residue, L-Tyr residue, L-Ala residue, L-Trp residue, L-Asn residue, L-Met residue, L-Ile residue, Gly residue, L-Asp (OBzl) residue or L-Leu residue. The invention discloses a preparation method of the 3H-imidazo[4,5-c]pyridine-6-formyl-amido acid benzyl esters, discloses HT-29, K562, A549 and HL60 tumor cell growth inhibition effects of the 3H-imidazo[4,5-c]pyridine-6-formyl-amido acid benzyl esters, further discloses S180-loading mice tumor growth inhibition effects of the 3H-imidazo[4,5-c]pyridine-6-formyl-amido acid benzyl esters, and also discloses use of the 3H-imidazo[4,5-c]pyridine-6-formyl-amido acid benzyl esters as antitumor drugs.