Abstract: During the operation of a solid oxide fuel cell （SOFC） stack, the sealant layer is usually confined in the narrow space defined by adjacent components, and its geometric constraints exert a crucial impact on sealing performance. To more accurately analyze the hermetic performance of SOFC stacks under actual operating conditions, High-pressure atomization spraying technology was adopted to prepare glass-based sealant layers. Referring to the actual structure of SOFC stacks, a test fixture with bosses of specific heights was designed. These bosses come into contact with adjacent components during the loading process, and part of the external load is borne by the boss structure, thereby limiting the maximum compressive deformation of the sealant layer and simulating the sealing state under geometrically constrained conditions in the stack. The feasibility of preparing SOFC glass-based sealant layers by high-pressure atomization spraying was verified. Meanwhile, the focus was placed on investigating the influence of the sealant width （the length of the sealant layer along the shortest gas leakage path） on hermetic performance, as well as the matching relationship between the sealant height （the spacing between adjacent components where the sealant layer is located） and the sealant thickness （the thickness of the sealant layer after spraying and before sintering softening）. The results indicate that the glass-based sealant layers prepared by high-pressure atomization spraying exhibit a uniform and dense structure after high-temperature sintering, with tight interfacial bonding to the SUS430 interconnect. Within the range of experimental parameters in this study, increasing the sealant width can effectively reduce the gas leakage rate. Even if the ratio of sealant thickness to sealant height remains consistent, it cannot guarantee favorable hermetic performance; The sealing effect still depends on the absolute difference between the sealant height and the sealant thickness. At 750 ℃ with an inlet pressure of 6 kPa, the sealant layer underwent a 300 h long-term thermal stability test and 8 thermal cycle tests, and the gas leakage rate was less than 0.003 4 mL/(min·cm), demonstrating excellent structural stability and thermal cycle resistance.