The invention relates to a phase-change heat storage device for greenhouse temperature control. The phase-change heat storage device comprises an aluminum alloy paraffin block (1), an aluminum alloy hanging paraffin box (2), a hanging support plate (3) and a heat insulation layer (4), the specification of the aluminum alloy paraffin block (1) is 390*190*190mm, a cavity shell of the block is made of aluminum alloys, paraffin is injected into the paraffin block through a packaging opening (7) and sealed, and the aluminum alloy paraffin block is bonded on the inner surface of the north wall of agreenhouse. The specification of the aluminum alloy hanging paraffin box (2) is 240*190*480mm, a cavity shell of the box is made of aluminum alloys, paraffin is injected into the paraffin box throughthe packaging opening (7) and sealed, the paraffin box (2) is placed on the hanging support plate (3) and tied on the upper hanging support plate (3) through a hemp rope (5), and the hemp rope is connected on the aluminum alloy box through a knob (6). The device is based on good phase-change latent heat characteristics of paraffin serving as a phase-change material, heat is absorbed and stored inthe daytime, excessive temperature caused by heat accumulation in the greenhouse is avoided, the temperature is reduced to gradually release heat in the nighttime, heat environments by needed by cropgrowth in the greenhouse are maintained, freezing damage to crops is avoided, renewable solar energy is sufficiently utilized, good indoor thermal environments are created, energy consumption is reduced, artificial heating is decreased, and greenhouse production benefits are improved.