The marked increase in oil fuel demands is related to the limited capacity of this nonrenewable energy. The consumption of fossil fuels raise the petroleum value, moreover, it causes harm to the environment. These days, Hydrogen, a renewable energy source, is used as a clean and powerful fuel widely. Hydrogen could be a suitable substitute for fossil fuels due to its special featured (e.g. water production after ignition, high octane and energy, renewably feature, and carbonless feature which cause a dramatic decrease in the toxic emissions). One of the most important application of Hydrogen is the consumption of this fuel as a supplement fuel. Hydrogen is separated from water by using Hydrox generator; and then it is injected in vehicle engines. In this work, design, production, and assembly of Hydrox generator are studied on two different Pride automobiles, one of them was a fuel injection car with a Sagem ECU and another was a carburetor car. Next, The preparation stages of the vehicle and control system changes were completed before the Hydrox gas injecting, and by field test run exhaust gasses analysis, before and after the gas inject, the injection effects of this supplement fuel on consumption, decreasing of emissions, and decreasing of the exhaust temperature were presented. Obtained results shows that special properties such as increase of quantity of 40 percent octane, stoichiometric ratio 2.5 times, thermal energy 3 times and flame speed 8 times higher in comparison to gasoline change this type of gas to a perfect complement for inject into car manifold, so that it can be reduced the fuel consumption by the optimum design of generator and sufficient inject of this gas without any power reduction and improved combustion and trauma decreasing. In addition, existence of waste water after ignition makes that the performance of this generator is similar to water injection manifold system. This property decreases heat combustion area and also increases efficiency and density. As well as waste water inside manifold reduces both heat exhausted and nitrogen oxide and hydrocarbon. The chemical composition of carbon monoxide with water vapor causes this gas converts to carbon dioxide and hydrogen, and not only lake of carbon in hydrogen fuel reduces emissions of carbon, but also oxygen does not react with carbon and returns to the environment again, the injection of hydrox gas, reduces emissions broadly . Keywords: Hydrogen, Hydrox generator, Electrolysis, decreasing of emissions, decreasing of fuel consumption, decreasing of the exhaust temperature