The fuel adaptability of a certain type of gas turbine combustion chamber is systematically investigated in response to the characteristics of blast furnace gas composition and its significant fluctuations in its calorific value. By coupling the detailed chemical reaction mechanism with numerical simulation methods, the comprehensive performance characteristics of the gas turbine combustion chamber under different calorific values and composition conditions were obtained, with a focus on analyzing the distribution of temperature and concentration fields and their influencing mechanisms. The results show that, under the same initial conditions and fuel calorific value, as the volume fraction ratio of H₂ to CO in the gas increases, the average temperature at the combustion chamber outlet decreases from 1 769.35 K to 1 710.11 K, the temperature distribution coefficient decreases from 0.044 to 0.016, the NO_x emission concentration at the outlet decreases from 7.56×10^–6 mol/m³ to 1.49×10^–6 mol/m³, and the CO emission concentration decreases from 993.98×10^–6 mol/m³ to 421.95×10^–6 mol/m³, and the combustion efficiency increases from 98.48% to 99.14%. As the volume fraction ratio of CO₂ to N₂ in the gas increases, the average temperature at the combustion chamber outlet decreases from 1 739.30 K to 1 694.99 K, the temperature distribution coefficient fluctuates in the range of 0.032~0.045, the NO_x emission concentration at the outlet decreases from 3.18×10^–6 mol/m³ to 1.39×10^–6 mol/m³, the CO emission concentration increases from 633.73×10^–6 mol/m³ to 832.45×10^–6 mol/m³, and the combustion efficiency decreases from 98.89% to 98.56%. In addition, as the fuel calorific value increases, the average temperature at the combustion chamber outlet significantly increases from 1 587.30 K to 1 862.39 K, the temperature distribution coefficient shows a downward trend, the NO_x emission concentration increases from 0.29×10^–6 mol/m³ to 18.66×10^–6 mol/m³, the CO emission concentration increases from 459.25×10^–6 mol/m³ to 1 030.61×10^–6 mol/m³, and the combustion efficiency decreases from 99.14% to 98.33%. Finally, 20 sets of data are selected for nonlinear surface fitting. For the blast furnace gas with a heat value range of 3~5 MJ/m³, all the the R² values of the fitting formula are greater than 0.90, indicating this formula can provide a theoretical basis for the control of low-heat-value fuels in gas turbine combustion chambers.