The National Treasure Mural Painting in Josadang Shrine of Buseoksa Temple is a Goryeo Dynasty mural painted on a wall made of clay. GPR exploration, a non-destructive investigation method, was conducted to d etermine w hether t he c ause o f wall c racks was related to the frame. A method of transmitting electromagnetic waves with a high frequency of 2 GHz through the surface of the mural was applied, and HH and VV data were acquired in the Y-axis direction. The survey was conducted with high resolution by setting the measurement line interval to 1 cm and the data acquisition interval to 1 cm very closely. The exploration method is similar to rebar exploration commonly used at construction sites. However due to the nature of earthen walls and wooden structures, they produce weak reflection signals, so when the data is processed in the same way, noise is amplified in the image. This may lead to errors in interpreting the results. In data processing, images were derived by applying the optimal gridding method. As a result of the investigation, it was determined that the wall framework was composed of Gasisae, Seol-oe, and Nul-oe that can be seen in a Korean Hanok building, and it was confirmed that wall cracks occurred on the location of the Gasisae.