【Abstract】 Objective To construct an eukaryotic expression vector including the fulllength encoding sequences of human eukaryotic translation initiation factor 3 Subunit C (EIF3C) and to transfect it into FaDu cell line, which provides a foundation for studying the biological function of EIF3C.Methods Total RNA was extracted from FaDu cell line and the fulllength encoding sequences of EIF3C (NM_0010378082) was amplified from cDNA fragment by specific PCR primers. After double enzyme digestion, the digested PCR products were cloned into vector pCMVBlank, and construct the eukaryotic expression vector pCMVEIF3C. The expression of EIF3C in FaDu cell line was detected by realtime PCR and Western blot after the recombinant plasmid transfected into FaDu cell line The FaDu cell line was transfected with vectorfree as the vectorfree group, vector pCMVBlank as the pCMVBlank transfected group, and vector pCMVEIF3C as the pCMVEIF3C transfected group. The mRNA and protein expression levels of EIF3C in pCMVEIF3C transfected group were compared with vectorfree group and pCMVBlank transfected group, as well as vectorfree group and pCMVBlank transfected group. The physical and chemical properties of amino acid sequences, phosphorylation sites, secondary structure and threedimensional structure of human EIF3C were analyzed by bioinformatics website and software. Results The sequencing results indicated that the human EIF3C sequence was correct in the constructed eukaryotic expression vector pCMVEIF3C. Transfection experiments showed that the mRNA level of EIF3C in vector pCMVEIF3C transfected group was 708 and 802 times higher than vector pCMVBlank transfected group and vectorfree group (P＜0.001), and protein expression levels of EIF3C were significantly increased than these groups. EIF3C protein is composed of 913 amino acids. It is predicted to contain 27 phosphorylation sites. The secondary structure of EIF3C protein is mainly alphahelix and random coil. Conclusion The recombinant eukaryotic expression vector of pCMVEIF3C was successfully constructed, and overexpressed in cell line of human squamous cell carcinoma.