The invention discloses a comprehensive processing system for generating power by sterilely burning garbage on the surface of water in a hydropower station. The comprehensive processing system comprises a garbage accumulation bin, a sterilization chamber, a cutting system, a mixing and stirring machine, a compressor, a drying chamber, a pelleting machine, a fuel bin, a burning chamber, a combustion improver bin, a binding agent bin, a boiler and a turbine, wherein an ash bin is arranged below the burning chamber, and is sequentially connected with a sieving machine, a crushing machine, a melting tank, a metal adsorbing and recycling tank, a filter net, an evaporation chamber, a calcining chamber, a natural cooling bin, a grinding machine, a water tank and a mineral powder bin. According to the comprehensive processing system, garbage is sterilely treated to form a new fuel for burning, the fuel is brunt to generate heat and the boiler is enabled to generate vapor to push the turbine to rotate to generate power, a considerable energy is obtained, and the burnt ash can be converted into a cement additive with high utilization value and economic value through reasonable process and equipment; the comprehensive processing system has a very high social value.