The invention relates to a biological purification retention zone for a multifunctional sponge city municipal road and a construction technology of the biological purification retention zone. The biological purification retention zone comprises a waterproof geotechnical cloth layer, a water storage and drainage layer, a water storage layer, a water-permeable layer, a filter layer, a planting layer, a water-permeable pipe and a water drainage system, wherein the water storage and drainage layer, the water storage layer, the water-permeable layer, the filter layer and the planting layer are sequentially laid form bottom to top, the upper surface of the planting layer is in a downward-sunken arc shape, the water drainage system is arranged in the middle of the planting layer and comprises anoverflow pipe, a siphon and a main drainage pipe, and the overflow pipe extends out of the surface of the planting layer. According to the biological purification retention zone, urban inland inundation is reduced, when the rainwater amount is large and rainwater is accumulated in the middle of a planting soil layer by a certain amount, excessive rainwater is sucked into the overflow pipe throughthe siphon and drained through the main drainage pipe, thus the rainwater is effectively drained, the various functions of water penetration, water storage, water purification, water retention, waterdrainage and the like are achieved, and the municipal road is incorporated into a part of a sponge city.