This paper presents a preliminary design and performance analysis of a supercritical CO₂ (SCO₂) heat exchanger for an SCO₂ power generation system. The purpose of designing a SCO₂ heat exchanger is to provide a high-temperature and high-pressure heat exchange core technology for advanced SCO₂ power generation systems. The target outlet temperature and pressure for the SCO₂ heat exchanger were 600 °C and 200 bar, respectively. A tubular type with a staggered tube bundle was selected as the SCO₂ heat exchanger, and liquefied petroleum gas (LPG) and air were selected as heat sources. The design of the heat exchanger was based on the material selection and available tube specification. Preliminary performance evaluation of the SCO₂ heat exchanger was conducted using an in-house code, and three-dimensional flow and thermal stress analysis were performed to verify the tube’s integrity. The simulation results showed that the tubular type heat exchanger can endure high-temperature and high-pressure conditions under an SCO₂ environment.