The study of the long-term behavior of the prestressed continuous beam is vital for the design and the appliance of wood structures in engineering. In this study, long-term experiments were first conducted to determine the long-term creep behavior. Afterward, the prestress of the long-term beam was regulated to the initial state, and we carried out short-term flexural experiments to explore the effect of prestressing regulation. The influences of prestressed value and the number of prestressed steel wires on the mechanical properties of the continuous beam were investigated and discussed. The experimental results demonstrate that the creep reduced the stress in the steel wires, weakened the effect of prestressing, and increased the tensile stress at the bottom of the beam, which led to a reduction in the bearing capacity of the beam. The prestressing regulation could increase the moment arm, so the bearing capacity of the beam was improved.