The core technology in pile foundation underpinning is the combination of old and new concrete surface connection method and performance. Based on the background of certain city tunnel crossing the viaduct pile foundation underpinning the engineering , this paper proposes a new mode of connection: rough surface+ planting bar drilling (adhesives ) + Spray interface adhesive. The experimental designed three specimens, the boundary surface within the scope of basic guarantee every 30 cm×30 cm into a steel bar, and part of the beam specimen strengthening, has carried on the static loading test. Conclusion: the combined surface connection way has higher shear bearing capacity of up to9.208×10 3 kN/m 2; And improving the new casting beam of stirrup reinforcement ratio has a larger effect to improve the interface shear bearing capacity; Planting bar in the old and new combination has played a major role in surface shear capacity, the border between old and new concrete surface, namely in the middle of the bar has the greater force; Planting bar located in both ends has the smaller force. Results show that the connection form construction by rough surface+ planting bar drilling (adhesives) + Spray interface adhesive is safe and reliable using in large axial force of pile foundation underpinning.