Abstract: Blast furnace gas （BFG） is the core carrier of CO₂ emissions in the long steel production. To solve the carbon reduction problem under the "dual carbon" goals, this paper proposed a new process of biomass co-reforming BFG, which realized deep carbon fixation in the system and significant increase in the calorific value of syngas by directed the reduction of CO₂ to CO. This paper used HSC Chemistry software to build a thermodynamic equilibrium model of the reforming process and systematically investigated the effects of gasification temperature, n（C）/n（CO₂）（molar ratio）, and system pressure on gasification performance. Based on the process parameters obtained from calculation and energy balance, the optimal efficiency of the reforming process was determined. The results show that moderately increasing the gasification temperature and n（C）/n（CO₂） ratio can significantly improve the quality of syngas, but excessively elevating these operating parameters will lead to a sharp increase in heat loss and limited conversion efficiency, while increasing the system pressure has inhibitory effect on the syngas yield. Comprehensive evaluation shows that under the optimal conditions of 1 000 ℃, n（C）/n（CO₂）= 10∶3, and 0.1 MPa, the carbon conversion rate and syngas yield of the system are both as high as 99%, and the higher heating value （HHV） of the produced syngas reaches 209.80 MJ/kmol, which is 2.41 times higher than that of the original blast furnace gas. Further economic benefit analysis shows that for every ton of biomass co-reformed with 1 767.36 m³ of blast furnace gas, 3 314.55 m³ of high-calorific value syngas can be produced, creating a value of 5 668.59 yuan, demonstrating significant industrial application potential and economic feasibility. The biomass and blast furnace gas co-reforming technology developed in this study provides important theoretical support and engineering reference for the efficient and high-value utilization of by-product gases in steel enterprises and for pollution reduction and carbon emission reduction.