Abstract: An new type of prestress underpinning technology is presented.By means of screwing high strength bolts,underpinning beams are forced to bend to get prestress up?word, on the other hand, bearing columns are unloaded to zero?stress condition and sawed off.Compared with current underpinning technologies, the new technology features direct and?efficient prestressing, simple construction and without damage to existing structures etc.An application of the technology to a?practical project is introduced in detail.