Abstract: This paper presents the simulation of the dynamic performance in the furnace of a 600-MW ultra-supercritical wall type tangentially-fired boiler in Liaoning Province. The diameter of the simulated inscribed circle and the dynamic performance of the furnace are studied and the simulation results are then compared with those from cold dynamic testing, which demonstrate its high fullness of the furnace field. Additionally, part of the high-temperature gas reflows back to the base of the flame in the four corners of the furnace, which is conductive to the stability of the combustion flame. Rising rotary air flow is formed in the center of the combustion zone with no primary air jets scouring the furnace wall. These results are fully consistent with the cold dynamic tests. Due to the strong rigidity of the primary air jet, the rising rotary air still has a large amount of residual rotation at the exit of the furnace. Therefore, there exists speed difference at the furnace exit. The simulation results can reflect the exact dynamic performance in the furnace and thus provide reference datum for the design and innovation of this type of boiler.