A three-dimensional lightweight steel framework comprising a beam, a purlin and/or a stringer, a column, a wall body, a floor slab and/or a roof, and a lateral-force-resistant rod and/or tension braces. The beam is a continuous double beam comprising two identical or different continuous single beams attached at both sides of the column, the continuous single beam and the column are continuous and not interrupted at a cross joint of the continuous single beam and the column. The present invention has advantages of simple structure and low manufacturing cost.
