Abstract Fringe images of overlapping micro-twin boundaries in a f.c.c. Ni-Cr alloy have been observed by trausmission electron microscopy. It is shown that the average intensity of the fringe images in the overlapping boundary is either much higher or much lower than that of the single boundary depending on the sign and value of the deviation parameters. The contrast of fringes will reverse when one changes the sign of deviation parameters for the matrix and/or the twin. Comparing with the well-known α-fringe and δ-fringe, overlapping twin fringes have special features which may arise from the anomalous absorption-anomalous transmission effects and the dynamic multiple beam interference among the matrix-twin-matrix or twin-matrix-twin. Using Van Dyck's iterative method, simulation images were calculated which are in good agreement with experimental observations.