This paper proposes a hierarchical distributed power flow (DPF) algorithm for multi-TSO-multi-DSO power systems. The algorithm includes a Ward-equivalence-based multi-TSO DPF at the TSO-TSO level and a single-TSO-multi-DSO DPF at the TSO-DSO level. The algorithm also introduces iteration variable correction and approximate TSO-DSO level solution techniques to improve convergence. The proposed algorithm is designed to effectively improve convergence of DPF algorithm for multiple TSOs and DSOs, reduce power losses, and enhance the stability of power systems. Numerical experiments demonstrate the accuracy, convergence, and efficiency of the proposed algorithm and the convergence improvement techniques.