A very long time ago, Taiwan was a trench containing sedimentary rock debris and sediment. The sophisticated geological structure nowadays was formed by interactive reactions between sedimentation, metamorphism, orogenic movement, land and ocean rising and submerging over long term.

The Yushan National Park sits at the center of Taiwan with the oldest layer on the east side of Central Mountains, namely the Tananao Complex of the metamorphic rock base, which is also one section of the most ancient layers in Taiwan.

The rock layers in Yushan National Park are extremely fragile. With highly active geological structures of faults, joints, and folds, the layers are easily affected by weathering; therefore, there are many dangerous collapse and cliffs in the Park. When children pass these places in Yushan National Park, particular attention to safety and awareness of falling rocks is necessary.