The optimum locations of the outriggers are analyzed for the outrigger-braced structure with the core being uniform in sections throughout the height of the structure. The analysis is carried out with the flexibility method by considering the compatibility of the column’s axial de-formation. The optimum objective aims at reducing the top-drift by finding the locations of the outriggers. The procedure of optimum analysis for the outrigger-braced structure is presented in detail in the paper. Various lateral loading cases are considered in the analysis, including uniformly distributed loading, triangularly distributed loading, and the loading with parabolic distribution. The influences of various structure parameters such as the flexural stiffness of core, outriggers, and columns are all discussed. Numerical results are presented and discussed. The results for the structures with different number of outriggers are given. Eventually, the efficiency analyses are also given with the determined optimum locations. The results between the structures with non-uniform core and uniform core are compared to show their difference of the optimum locations of the outriggers, and relevant efficiencies in reducing the top-drift.