Currently, microtubular solid oxide fuel cells (SOFC) bundles are under development, which consist of microtubular SOFCs and porous cathode matrix where the SOFCs are integrated. In this study, a new fabrication process of the sealing layer for the microtubular SOFC bundles was examined using MgO-magnesium boro-silicate glass composites. A sheet and paste of these composites were prepared, and the microstructure and shrinkage behavior of the composite glass layers were investigated to minimize the deformation of the layer during fabrication process. The results indicated that using 100% glass sheet with the composite glass pastes appeared to be effective in reducing the shrinkage of the glass layer. In addition, the effect of sheet thickness on the shrinkage behavior was investigated and showed that the shrinkage ratio reduced as the sheet thickness decreased, and the shrinkage of about 0.2% was achieved at the sheet thickness of about without defects or shape deformations. Thus, this fabrication method turned out to be effective for constructing a sealing layer for the microtubular SOFC bundles.