Qixing Mountain is located on the Datun Volcano Group and the tallest mountain at the rim of the Taipei Basin. It located in the center of Yangmingshan National Park, the main peak is 1,120 m tall (above elevation).
It began erupting about 700,000 years ago. There was a crater at the peak but it became seven small peaks due to post-eruption erosion.
The mountain has faults running across the southeast and northwest contours with volcanic landforms like hot springs and fumaroles.
Shamao Mountain is a round volcanic dome looking like a black gauze cap. As the lava was more viscous when the mountain was formed, it gradually became a tholoid, also known as a cumulo-dome volcano. Shamao Mountain is a parasitic volcano of the Cising Mountain group.