The invention discloses a power generation system of a high-rise building energy-accumulation water pipe. The power generation system comprises an energy-accumulation water pipe, a sewer pipeline device, a high-rise building, a water turbine and a power generation system, wherein the energy-accumulation water pipe device is arranged beside a sewer pipeline near the high-rise building, rainwater and domestic sewage are led into the energy-accumulation water pipe through a diversion pipeline, when the water level in the energy-accumulation water pipe exceeds a certain height H1, power generation can be started, and power generation can be stopped when the water level is reduced to H0, water can flow out of the sewer pipeline through a rainwater inlet pipeline when the water level exceeds the largest height H2, the water turbine drives an electric generator for power generation, and the generated electricity can be synchronized and also can be directly supplied to a high-rise tap water boosting pump. The sewage of the high-rise building can be stored through a plurality of energy-accumulation water pipes, and are accumulated together for concentrated power generation, water resources can be reasonably recycled, the environment is improved, and the economic benefits, environment benefits and social benefits are obvious.