The utility model provides a container body side plate strengthen rib assembling structure for a steel container with a heat insulation layer, which comprises an inner plate, an outer plate and a plurality of strengthen ribs arranged in parallel. The strengthen rib is a vertical long rod piece with an Omega-shaped cross section. The strengthen rib comprises an inner plate connecting part positioned on an Omega-shaped top part of the strengthen rib and two outer plate connecting parts arranged on wings of two horizontal sides of the strengthen rib. The inner plate connecting plate is connected with the inner plate. The two outer plate connecting parts are connected with the outer plate by welding. The inner plate connecting part and the inner plate, and the outer plate connecting part and the outer plate are contacted by sides. The strengthen rib also can be a continuous Omega-shaped cross section or a Z-shaped cross section. The box body side plate strengthen rib assembling structure for the steel container with the heat insulation layer of the utility model ensures that the inner plate and the outer plate of the container body are connected into a whole by the sealed strengthen rib, thereby improving the integral strength, and meanwhile the connecting ways of dual-row and a plurality of rows are more solid than the ordinary connecting ways.