The application of Thermoelectric Generators for converting geothermal energy to electricity is investigated in this paper, considering the effects of various parameters on their efficiency. Using renewable energy is one of the latest solutions to tackle climate change, global warming, air pollution, the ozone layer hole, etc. In this regard, a thermoelectric generator (TEG), which is a device for converting heat energy to power, could be used in different renewable energy systems like solar or geothermal. Although their initial cost is lower than the other methods of converting thermal energy to electricity, their efficiency is lower than the most common techniques. Therefore, finding the optimum situation to increase the efficiency of combined devices with TEGs can increase the likelihood of using them in different industries. The parameters investigated in this paper were the temperature of the operating fluid in channels, the optimum mass flow rate, and the channel slope. The results have shown that with increasing temperature differences of the fluid in the channel, the efficiency of the designed system increased significantly. In addition, by increasing the mass flow rate of the operating fluid in the channel, power generation and the whole system efficiency increase up to a certain plateau value. Furthermore, the experimental results have proven that increasing the slope of the channel increased the amount of power generation but has not caused a noticeable change in their efficiency.