Abstract: A solar energy water heater includes a water pipe and a plurality of solar heat units transversely extended from the water pipe, wherein each solar heat unit includes a heat collecting tube is adapted for heating up the water within the heat collecting tube and a heat transferring tube disposed in the heat collecting tube to define a water conduit. The heat transferring tube has a water channel and an outer opening end extended towards to an outer closed end of the heat collecting tube to communicate the water channel with the water conduit of the heat collecting tube such that the water is guided to flow from the water inlet to each of the solar heat units to circularly flow between the water conduit and the water channel thereof so as to substantially heat up the water before flowing out at a water outlet of the water pipe.