We investigate the effect of different operating conditions on the combustion process of the wall-fired furnace. The flue gas temperature, furnace wall temperature, and spatial distribution of local heat flux on the wall of a laboratory-scale, gas fuel front wall-fired furnace are measured experimentally. Different combinations of operating conditions including swirl intensity (SI), air supply (AS), and burner combination (BC) are considered, and their influences on the combustion, heat-transfer, and heat flux distribution characteristics are explored. Among the operating conditions studied in this paper, the combustion process can be improved with the increase of SI as well as the inner secondary air (ISA) rate. Detailed local heat flux data are obtained and analyzed under various operating conditions. The results illustrate complicated variations over the entire furnace wall. The decrease in SI conditions significantly enhances the local heat fluxes near the bottom of the furnace (adjacent to the combustion region), where the mechanical integrity of the wall is of concern. The averaged local heat flux on the front wall is sensitive to the operating conditions. Preferable operating conditions for different BC conditions are identified on the basis of the non-uniform coefficients. The findings may help to improve the understanding of the heat flux distributions (in particular, in the wall-fired furnace) and give useful insights for the optimization, arrangement, and material selection of the heating surface.