Abstract: In tradition, the diagnosis of delamination in either grotto wall paintings or palace wall paintings is achieved by identifying the sound when lightly knocking on the wall by hand, such experience is practical in determining the area and degree of delamination, but it depends on subjective sensation, lacking some theoretical principles. Focusing on the propagation of high frequency pulse electromagnetic waves in layered lossy and dispersive medium and after the physical forward modeling experiment, this paper tries to locate delamination in polished wall paintings in Tibet by wall coupling antennas using RAMAC ground penetrating radar. It is shown that the ultra-wide band ground penetrating radar is capable of detecting delamination in vertical resolution of about 5 mm when it is equipped with a transmitting antenna of 1.6 GHz central frequency. It is a quantitative attempt to detect delamination in wall paintings, the research results promote technical improvement for conservation of wall paintings.