The invention discloses a gabion box ecological gabion river channel slope protection construction method. The gabion box ecological gabion river channel slope protection construction method is mainly characterized in that the defect that only the flood control function, the water diversion function, the drainage function, the impoundment function, the shipping function and the like of a river channel are often considered according to a traditional river channel slope protection structure, and the ecological function of the river channel is rarely considered is overcome. The gabion box ecological gabion river channel slope protection construction method includes the following steps that a cofferdam is constructed, a worktable is arranged, and a footing construction period is carried out; after gabion slope protection construction is over, gaps between surface course dimension stone are recharged with soil and watered, it is ensured that the gaps of dimension stone are filled with soil, and a dimension stone slope is covered by a layer of cultivating and planting soil; aquatic plants are planted underwater, and a lawn is planted on a bank of the river channel. According to a construction technology, water, cement and a formwork are not needed, and construction is convenient. The gaps between building stone can be manually or naturally filled with mud on earth, root systems of the plants can be deeply pricked into the slope through the mud between the building stone, so that engineering measures are combined with vegetation measures, and a soft overall protection face is formed. The requirements for water and soil conservation and environment greening are met, and therefore the original ecological environment is recovered.