The invention provides a segmental prefabricated assembled pier and a construction method thereof. A bent cap and a pier are divided into a plurality of standard segments; joint connection between every two standard segments comprises fixed connection for two parts, i.e., dry joint operation surfaces and wet joint operation surfaces; and all the standard segments are prefabricated in a factory andthen assembled on site. After being solidified, wet joint concrete bears load along with the dry joint operation surfaces, increasing the integrity of the pier; after the wet joint concrete is solidified, the assembling construction of the next segment can be immediately carried out, and therefore the curing period of the wet joint concrete is shortened. The segmental prefabricated assembled piernot only has all the advantages of a prefabricated assembled structure, such as high construction quality, less on-site operating personnel, high mechanization degree, low energy consumption and environment-friendliness, but also has the advantage of the dry joint operation surface, i.e., convenience and rapidness in construction, the advantages of a wet joint, i.e., good integrity, high anti-shearing capability, and the like. On the other hand, the invention further provides a construction method for the segmental prefabricated assembled pier.