The worsening environmental pollution has increased the interest in developing eco-friendly technologies. The purpose of this study is to develop an aero-heat exchanger to reduce the emission of environmental pollutants. The operating conditions of an aircraft are extremely harsh, leading to challenges with the determination of appropriate materials and structures that can withstand the severe conditions. In addition, since the tubes brazed to the tube-sheet are structurally fragile, it is essential to assess the structural integrity of tubes. In this study, the overall structural integrity of the tubular heat exchanger under development was evaluated. An appraisal of the junctions between tubes and tube-sheet, which are the most critical parts, was conducted. A finite element (FE) analysis was employed for the assessment of structural integrity. FE analysis was used to evaluate the brazed joint of tubes using a model in which specific tubes were designed to withstand the high temperature of the tube-sheet. The evaluation was carried out compared with the fatigue strength of Inconel 625, the material constituting the heat exchanger.