© To meet the target of using renewable energy and electrification in remote areas, Indonesia needs to develop pico hydropower plants. One of the picohydro turbines that can be used is the propeller openflume turbine. To obtain the optimum performance, a numerical study of the effect of the gap between blades was carried out. This study analyzes 3 different blades by using the computational fluid dynamics method. The difference between the three blades is the gap between the blades. The first blade is designed with gaps, the second blade is without gaps, and the third blade is designed with overlap gaps. Based on the numerical results, it is shown that the gap on blades of propeller openflume turbine affects the performance of turbine with the overlap turbine has a better performance than the gap and no-gap blade. The overlap blades generate 9.48 Watts power and 8.8% efficiency at 202 rpm.