Representing the earlier forms of Korean rock-carved images of Buddha, the Standing Rock-Carved Triad Buddha in Taean-gun features a Bodhisattva flanked by two Buddha images in a square niche on a fan-shaped rock in a unique formation, different from a typical triad arrangement of one Buddha image at the center accompanied by two Bodhisattvas at each side. The two Buddha images share almost the same details of an engaging smile on a voluminous face, wide shoulders and a sturdy body, U-shaped wrinkles, the way of putting on the robe, and thick but sharp lotus petals of the pedestal. Standing between the two Buddha images, a little smaller in size is the Bodhisattva statue is wearing a coronet, which has no pattern presently but is thought to have had one before. Its oval, plump face is putting on a calm smile, and its cylinder-like body is standing straight. The robe covering the shoulders flows down and crosses around the lap. The two hands are put together upon the stomach holding a sacred bead and the right hand faces up with the left one down. With its lotus pedestal of the Baekje period, Standing Rock-carved Triad Buddha in Taean-gun is recognized as having exceptional sculptural value. Located at a key point for cultural exchange with China, this work of art is also essential in studying the mutual relations with Chinese Buddhist statues. Its formative patterns preceding even those of Rock-carved Buddha Triad in Yonghyeon-ri, Seosan (National Treasure No. 84) assure its historic value as a national treasure and the oldest rock-carved Buddha image of the Baekje period.