Heat collector water storage tank

The utility model relates to the technical field of solar heating, in particular to a heat collector water storage tank. The heat collector water storage tank comprises a phase-change material layer which is arranged between an inner container and a heat preservation layer. When the water storage tank is in the process of heat storage, the phase-change material layer arranged on the inner container is in the process of heat absorption, and due to the fact that a cold water inlet pipe is arranged on a lower end cover, in the actual process of water flowing out, water temperature in the whole inner container is distributed step by step in an top-hot and bottom-cold mode. When hot water needs to be used, a water outlet pipe on an upper end cover is opened, hot water on the upper layer reaching set usage temperature can flow out from the water outlet pipe, water on the lower layer rushes to the upper layer, temperature is reduced step by step, when the water temperature can not reach the set usage temperature, th