In this study, to improve the penetration of the anti-p21Ras scFv into tumor tissues via endocytosis, we connected the RGD4C sequence to the N terminus of the anti-p21Ras scFv to construct RGD4C-p21Ras-scFv prokaryotic expression vectors, then the fusion protein RGD4C-p21Ras-scFv (RGD4C-scFv and RGD4C-linker-scFv) was expressed and purified and subsequently investigated the effects of targeting and penetrating the human colorectal cancer cell line SW480 as well as the antitumor effect in vitro. Here, HRAS is linked to colorectal cancer.