The Screw Turbine is a Hydroelectric Power Generation Tool using the Archimedes principle to convert the potential energy of water into energy or power. then the purpose of this research is to design and build variations in the diameter of the turbine screw blade. This tool that has been made is used as a source of electricity and lighting systems in rural communities. This screw turbine uses components such as tool frames, generators, gear wheels, chains, pillow block bearings, propellers, universal chain stabilizers, resistors, lights and switches. From all measurements that have been carried out, it is obtained data that the generator output using a blade diameter of 26 cm when averaged is 8.32 watts and when using a blade diameter of 30 cm is 6.21 watts, so it can be seen that the power generated when using a blade diameter of 26 cm has a greater value than when using a blade diameter of 34 cm or 30 cm. The method used in this research is the experimental method.

Keyword: Water, Power Generation, Screw turbine, variation Blade diameter screw turbine.