The volcanic eruption during Holocene of Hainan Island, China, has elevated the coastal bays to be terraces, blocked the river mouths, forced river channels migration and elevated the abundant river mouths to be deep erode-meandered bays, and volcanic rocky coast offered the basements for coral reef development. The volcanic activities have changed coastal landforms, slops, dynamic conditions, sedimentary characteristics and the trends of coastal evolution. The development of volcanic coast has shown a multi-affection of both inner and outer dynamic processes of tectonic, marine hydro-dynamics and biological factors. Comparatively, Hawaii volcanic coast is characterized by a volcanic-island chain formed by the lateral movement of the oceanic plate moving over a stationary hot spot. The ages of the islands increase toward the left, and new islands will continue to form over the hot spot. Recently, lava flows of Kilauea eruption continue the island-building processes, produce a barren volcanic landscape of creator bay, lagoon etc., that served as a foundation for coral reefs and lives: plants, animals and humans. Also, the eruption has changed the local atmospheric environment. Plants, animals and humans. Also, the eruption has changed the local atmospheric environment. Plenty precipitation of the tropic islands develops fertilized soil, which produces favorable condition for luxury forests and bio-diversity. The Pacific volcanic islands are the precious location of tropic biological resources and ecological environment. Volcanic debris daily erupted by active volcano of Sakura Island, Japan have buried the parts of island, highways, houses, temples, and have caused muddy flow disasters often, especially during thunder storm periods, as a result, they have changed the dynamic processes. What is more important, besides the change of coastal geomorphology, dynamic processes and the trend of coastal evolution, is that the volcanic activities might lead to a series of severe disasters.