Toll-like receptors(TLRs) play key roles in the initiation of the innate immune system by recognition of conserved foreign molecules called pathogen-associated molecular patterns. TLR 3 is located in endosomes and it recognizes virus infection by sensing dsRNA which is produced during virus replication. Especially, TLR3 is related to CNS virus infection. However, the activation mechanism and downstream signaling pathways are unclear because of considering only ectodomain and lack of complete structural information. In this research, we focused on expression and purification of full-length of TLR3 which is essential for revealing activation mechanisms by structural studies. To provided correct post-translation modification and lipid environments, TLR3 was expressed by the mammalian expression system – bacmam. Solubilization detergent that is one of the most important for membrane protein stability could be determined by FSEC. Finally, the sample quality was check by negative-stained TEM.