Abstract: A method for removing scale from a turbine blade in a geothermal power generation system has been developed. The developed method for removing scale from a turbine blade is characterized in that an alkaline solution and a chelating solution are injected into geothermal steam flowing into a turbine during power generation and geothermal scale formed adhering to the turbine blade is removed using the injected solutions. The present removal method can remove the scale adhering to a geothermal turbine blade in a short amount of time by improving the scale removal effect than heretofore. Further, a method for geothermal power generation preventing scale adhesion to the turbine blade is provided and a geothermal power generation system can be provided that enables continuous operation without performing opening and cleaning the turbine, even when geothermal steam containing 0.1 ppm or more of SiO2 and/or Cl is introduced into the turbine.