Aiming at the present status of lacking the study on the relative strength between internal waves and water upwelling around the world, a new method of approximate calculation was proposed to calculate the relative contribution to mixing by the internal waves and water upwelling under various conditions. At the same conditions of temperature gradient, thickness of the thermocline and aerator outlet position, when the aeration flow rate increased from 62.5L/(h·m³) to 125L/(h·m³), the contribution rate of the internal waves to the artificial mixing dropped from 82% to 50%. At the same conditions of temperature gradient, aeration rate and aerator outlet position, with the increase of thermocline thickness, the contribution rate of the internal waves to the artificial mixing increased from 78.5% to 83.5%. Compared with the cases without the wave dissipation device, the effective power rates for mixing were increased by more than 40%. A/T is the most fundamental factor which influences the mixing by the internal waves. Experimental results indicate that the internal waves only require very little energy to induce strong mixing, which is totally different to that of water upwelling induced by aeration, namely the mixing by internal waves was more efficient in energy consumption. There are broad prospects of applying the internal waves to destroy stratification and to improve water quality in stratified source water reservoirs.