CD1d belongs to MHC class I relatives, and presents lipids and glycolipids through T cell receptors (TCRs) on T cells and Natural killer T (NKT) cells. CD1d displays both self-lipids common in mammalian and foreign lipids specific for microorganisms. A number of structures of CD1d proteins complexed with its ligands were reported so far and they revealed ligand recognition mechanisms and TCR recognition manners. To date, the structures of CD1d in protein data bank (PDB) were mostly expressed in insect cells. We tried another host, silkworm larvae as the expression host and compared the expression level and the property of the CD1d proteins between insect cells and silkworm. CD1d was expressed in either of insect cells or silkworm larvae and purified by sequential column chromatography. Enough amount of proteins were prepared and the properties of the purified proteins were confirmed by MALDI-TOF MS analysis and the molecular weight of the CD1d proteins were slightly larger than the theoretical value due to the N-linked glycosylation. Digestion of the glycosyl chains by the endoglycosidases, EndoH and PNGaseF, showed that proteins from silkworm were uniformly glycosylated than those from insect cells and they were suitable for structure analysis. For the crystallization of CD1d proteins prepared by silkworm, commercial screening kits were used and several conditions were found. After optimization of the crystallization conditions, X-ray diffraction datasets were collected and structures of CD1d were solved by molecular replacement method. Here we present the protein preparation techniques using silkworm and discuss the structural characteristics of CD1d proteins in detail.