Syngas fuel generated by solar energy integrating with fuel cell technology is one of the promising methods for future green energy solutions to carbon neutrality. This paper presents a fuel preparation system for solid oxide electrolytic cell (SOEC) based on full spectrum utilization of solar energy, The short wave of sunlight provides the power needed for the co-electrolysis and the long wave provides the heat needed for the system. The thermodynamic model of each component is established, and the thermodynamic, economic and enviro nmental analysis of the system is carried out. Overall exergy efficiency and exergy efficiency of the three modes are 63.1% and 62.5%, 67.3% and 65.8% and 15.0% and 15.6% respectively under the design condition, considering the independent SOEC system, the SOEC subsystem with coupled heat recovery and the SOEC system with solar energy coupled heat recovery. The overall cost rate and CO₂ emission rate of the system are 9.79 USD/h and 0.04 kg/kWh, respectively, and the specific exergy cost is 0.086 USD/kWh. In addition, the influence of SOEC operation parameters on the system performance is discussed. When the current density, operating temperature, pressure and water vapor mole fraction are 0.64 A/cm², 1323.15 K, 0.1 MPa and 20%, respectively, the energy efficiency and exergy efficiency of the system reached the maximum.