A complete stress-strain curve model for concrete confined by rectilinear reinforcement was proposed. In this model, the confinement effect of rectilinear steel, including common hoops and square steel tube, was evaluated by using effective lateral pressure factor. Major variables influential in the confinement level of transverse hoops were contained in the effective lateral pressure factor in a relatively simple form. Comparisons between the expeimental and the theoretical results showed that the proposed stress-strain model can predicte not only the stress-strain curves of concrete confined by square steel tube fairly well, but also those of concrete confined by common hoops with various distribution shapes.