Water-Water direct mixing type heat exchange unit is mainly assembled by water mixing tank, circulating pump, backwater booster pump, temperature control device, control meter and control box etc. The heat exchange unit has high heat exchange efficiency, low production cost and outstanding energy-saving effect. The main character is that the primary high-temperature water is mixed directly with secondary low-temperature water in the mixing tank to finish the heat exchange. It use the primary water‘s pressure completely, reduce the power of circulating pump of secondary water to the full.