Abstract: In view of the problems such as long power supply links for fire distribution in high-rise buildings, complex interconnection of fire loads, and easy expansion of local faults under fire conditions, this paper studies the reliability design and power supply guarantee technology of fire distribution system. Optimization is carried out around dual-source redundancy, vertical zoning busbar, terminal differential protection, rapid power failure switching, load sequence startup, and online isolation of feeder lines. Application tests are conducted in a 30-story commercial and office building. The results show that the dual-power switching time is reduced to 2.17 seconds, the power supply voltage drop of fire pumps is reduced to 6.47%, the fault isolation time is reduced to 0.68 seconds, the non-fault circuit power supply rate is increased to 98.21%, and the power supply continuity and fault controllability of the system have been improved.