Abstract: Regarding tube burst issue of boiler superheater tube bundle during service, a full three-dimensional modeling and structured mesh discretization of the final stage superheater tube screen of a power plant boiler were carried out based on supercomputing platform. The Reynolds average Navier-Stokes simulation method and Lagrangian two-phase coupling model were used to systematically simulate the steam flow characteristics and oxide scale particle accumulation behavior inside the superheater tube screen. Effect of load change and oxide scale particle exfoliation on the steam flow distribution of the superheater tube screen was explored. Results show that the steam flow rate of the tube bundle with throttle holes is 5.63%-11.23% lower than that of other normal tube bundles without considering the thermal deviation on the flue gas side. The maximum flow rate deviation of the same tube screen reaches 6.3%, and locates in coiled tube bundle (tube bundle 17). The difference in steam flow velocity at the outlet of different tube bundles of the same tube screen under four load conditions ranges from 10.3% to 11.7%, which can lead to significant difference in the power of transporting oxide scale particles in different tube bundles. When the particle size increases from 500 μm to 2 000 μm under different conditions of oxide scale exfoliation in tube bundles, the probability of particle accumulation increases by 15% to 20%. Both of the maximum positive and negative deviation of flow rate for each tube bundle on the same tube screen exceed 6.6% under the condition of simultaneous exfoliation of oxide scale in the four tube bundles, which should be considered in the superheater design process.