Abstract: Due to the limitation of the blocking ratio of wind tunnel and the requirement of sufficient measuring points on the outdoor platforms of a thousand-meter-scale megatall building, the wind environmental experiment can only be conducted for a sub-configuration of the building. Therefore, the problem should be solved at first is:How to assess the pedestrian wind environment of outdoor platforms of the megatall building based on the experimental data of the sub-configuration? To solve this problem, characteristics of pedestrian wind environment of both the full model and the sub-configuration of the megatall building were investigated using the CFD simulations and wind environmental experiment. Firstly, comparisons of the experimental data and CFD results of pedestrian wind environment of the sub-configuration with different wind shields were conducted, and the results show good agreement. Therefore, the feasibility and credibility of the CFD simulations were validated. Secondly, distributions of pedestrian wind speeds on every platform of the full model with different wind shields were compared via the CFD simulations, and the most unfavorable outdoor platform was determined to be the platform 4 by using the quartiles method in descriptive statistics. Thirdly, the pedestrian wind environment of both the platform 4 of the full model and the platform 2 of the sub-configuration were compared via the CFD simulations, and an adjustment coefficient for the pedestrian wind speed from the sub-configuration to the full model was proposed. Therefore, a link between experimental data of the sub-configuration and pedestrian wind speeds on the platforms of the real megatall building was established, which lays a solid foundation for the wind comfort and wind safety assessment of the megatall building in the future.