Many of aged and damaged concrete structure have been revitalized with composite reinforcement. Flexural behaviors of composite-patched concrete specimens are characterized by high-sensitivity moire interferometry. The three-mirror, four-beam interferometry system and a compact loading system are used for obtaining singe patterns representing whole-field contour maps of in-plane displacements. It is seen from the calibration test for the loading system that the measured bending displacement is in excellent agreement with the displacement calculated by the beam theory. The crack opening displacement as well as the bending and the horizontal displacement fur the notched and unnotched specimen are investigated. The results also show that the notched specimen reinforced by a composite sheet has sufficient stiffness and strength compared to the original concrete specimen.