Mobile flood wall preferably comprising of plastic, characterized by support elements (1 through 5) as plates of a fitting thickness, each in the form of an equilateral triangle with one of the three equal outer sides as the base and wall elements (11 through 19) as rectangular plates of a fitting thickness lying on and connected to the water-side outer side of the equilateral support elements and therefore sloped at an angle of 60.degree., which forms the wall with the land side surface, wherein the water pressure on the wall elements is diverted by the support elements into the ground, and causes the surface structures of the base of the support elements to be pressed into and anchored in the ground, for sealing the ground against water and for the stability and the nondisplaceability of the flood wall.