The invention relates to a cascading type ecological planting tank for road surface runoff collection, purification and utilization. The cascading type ecological planting tank is formed by connecting a plurality of ecological planting tanks distributed along a highway route in series, wherein each ecological planting tank is formed by a vegetation layer, a planting soil layer, a permeating and purifying layer, an impervious layer, a supporting layer, a water storage layer and a permeating preventing layer from top to bottom, and the bottoms and the lateral surfaces of the vegetation layer, the planting soil layer, the permeating and purifying layer, the impervious layer, the supporting layer, the water storage layer and the permeating preventing layer are sealed. The plurality of ecological planting tanks are sequentially connected in series along a longitudinal slope of a highway from top to low, the water storage layer of the ecological planting tank at the higher position is connected with the permeating and purifying layer of the corresponding ecological planting tank at the lower position, and a reversed-U-shaped siphon is installed between the permeating and purifying layer and the water storage layer of each ecological planting tank. By means of the structure, comprehensive functions of road surface runoff collection, purification, storage, automatic guiding and discharging and comprehensive utilization can be achieved, and the cascading type ecological planting tank for road surface runoff collection, purification and utilization is suitable for road side afforest and central median afforest of places concentrated in rainstorm and uneven in rainfall distribution, road surface runoff collection, processing and utilization or emergency management of road surface dangerous goods transportation leakage.