The invention provides a heat preservation plant wall structure and a construction method thereof. The heat preservation plant wall structure comprises building main body section steel keels, plant area wall bodies, plant modules, plant wall covered edges and an intelligent irrigation system. The section steel keels are parallelly connected to the outer side surface of a building main body in a spaced mode in the vertical direction. The plant area wall bodies are parallel with the outer side surface of the building main body and hung on the outer sides of the section steel keels and comprise plant wall main body plates, filling layers and covering layers. Plant modules are arranged on the outer side surfaces of the plant area wall bodies in a matrix shape and comprise planting containers, planting bags, substrates and plants. The planting containers are connected to the plant area wall bodies through connecting pieces. The intelligent irrigation system comprises intelligent irrigation equipment and drop irrigation pipes. The intelligent irrigation equipment is mounted on the outer side of the building main body and above the plant area wall bodies. The drop irrigation pipes are connected to between the intelligent irrigation equipment and the planting containers. According to the heat preservation plant wall structure and the construction method thereof, the technical problems that as for a traditional heat preservation wall body, heat preservation performance is poor, a heat preservation layer is cracked and prone to falling off, the beauty performance is poor, and the safety hazards are large are solved.