The LinTT1 peptide is a tumor-penetrating peptide with the amino acid sequence AKRGARST. It targets peritoneal cancer (PC) by binding to the p32 (gC1qR) receptor. The LinTT1 can associate with iron oxide nanohelical (NWs) structures to form a nanocarrier that is taken up by peritoneal cancer cells in vitro and penetrates mitochondria; it also shows significant tumor-targeting and penetration effects in vivo in mice. Furthermore, LinTT1-functionalized nanocarriers combined with the pro-apoptotic peptide [D(KLAKLAK)2] demonstrate substantial tumor inhibition in a mouse peritoneal tumor model. LinTT1 peptide holds promise as a delivery vehicle for peritoneal cancer research.