The present invention relates to a ecological construction system for buildings with green walls. The system is based on the provision of an integral wall structure, one of the section of which comprises concrete and steel reinforced formwork as the main supporting structure, while the remaining part of the section comprises hollow cavities and arrangements of punched sections on the front or rear surface thereof, with drip-irrigation pipes and nozzles being provided therein. Plastic containers are housed in, and fixed to the punched arrangements distributed on the front or rear wall, which containers form a means for supporting natural or artificial substrates (soil, mineral fibers or wools) and also for the cultivation of plants, a channel being provided in the lower part of the wall structure for collecting, filtering and conveying water to a container for reincorporating said water into the irrigation system. The resulting system allows the growth of plants and vegetation on green walls for construction purposes and can be used on all types of new or existing buildings.