The invention discloses a phase change energy storage module and a preparing method thereof. The energy storage module comprises a heat exchange cavity used for storing a phase change material and a snake-shaped water inlet pipe used for water supplying; the heat exchange cavity comprises an upper transverse cavity, a lower transverse cavity and a plurality of heat exchange medium pipes, at least one liquid pouring opening is formed in the upper transverse cavity, a liquid draining opening is formed in the lower transverse cavity, and the liquid pouring opening and the liquid draining opening are provided with corresponding seal parts; the heat exchange medium pipes are axially arranged along the upper transverse cavity or the lower transverse cavity, the two ends of each heat exchange medium pipe are fixedly connected with the upper transverse cavity and the lower transverse cavity correspondingly, and it is ensured that the upper transverse cavity, the lower transverse cavity and inner cavities of the heat exchange medium pipes are communicated; the preparing method comprises the steps that after the phase change material is heated and liquefied, the phase change material is added into the heat exchange cavity through pouring, and after cooling and curing, through vacuumizing treatment, nitrogen or carbon dioxide gas is inflated for replacement and plug seal. The module has the beneficial effects that heat exchange between a cold and heat source and the phase change material is achieved, and stainless steel and a copper pipe in a packaging container are effectively prevented from being corroded.