Abstract: Supercritical carbon dioxide (sCO₂) Brayton cycle system demonstrates broad application potential in power generation, solar energy, hydrogen energy, and nuclear energy, effectively filling the technological gap for energy conversion systems in small-to-medium power scales with high-temperature heat sources. Heat exchangers, such as coolers and recuperators, are critical components for energy transfer within sCO₂ power conversion systems. To achieve the designed heat load within a limited space, these heat exchangers must possess highly efficient heat transfer capability, reliable performance under high temperatures and pressures, and an ultra-compact structural arrangement. Among various types of heat exchangers, the micro-channel diffusion bonding (MCD) heat exchanger is considered one of the most promising configurations for sCO₂ systems due to its compact structure, ability to withstand high temperatures and pressures, and stable manufacturing processes. The zigzag microchannel offers advantages of a simple structure, mature fabrication techniques, and strong heat transfer performance. This study involved the development and experimental investigation of test sections with deflection angles of 15° and 30°. Parameters including working fluid temperature, pressure, and flow rate were measured to analyze the flow and heat transfer characteristics and overall thermal-hydraulic performance. A total of 558 heat transfer data points and 196 flow data points were obtained. The results show that the Fanning friction factor for sCO₂ in the zigzag microchannel is negatively correlated with the Reynolds number (Re). An increase in the bending angle leads to an expansion of the recirculation zone, resulting in increased flow resistance at the same Reynolds number. Based on the experimental data, flow resistance correlations for the two zigzag microchannels were developed. For test section a#, 86.0% of the experimental data fall within ±40% of the newly established correlation. For test section b#, 92.2% of the data fall within ±25% of the correlation. The Nusselt number is positively correlated with the Reynolds number. A larger bending angle enhances fluid disturbance and disrupts the thermal boundary layer more significantly, thereby intensifying heat transfer. Furthermore, convective heat transfer correlations for the two zigzag microchannels were established. The results show that 77.1% of the data for test section a# and 75.6% of the data for test section b# fall within ±20% of their respective newly developed heat transfer correlations. The performance evaluation criterion (PEC) for the zigzag microchannel is found to be related to the bending angle and the Reynolds number, but is essentially independent of the Prandtl number. The PEC values for both structures increases with Re. However, within the range of Re＜10 000, the zigzag microchannel with a 15° bending angle exhibits inferior comprehensive performance compared to a straight micro-channel. For Re＜20 000, the structure with a 30° bending angle outperforms that with a 15° angle. This trend reverses when Re exceeds 20 000.