The invention discloses a steel-plate-encased assembly type concrete column foot joint and a construction method thereof. The column foot joint comprises a prefabricated reinforced concrete column, a reinforced concrete foundation and a steel-plate-encased cylinder, and further comprises an annular rib plate, wherein the steel-plate-encased cylinder is integrally prefabricated with the concrete column and surrounds the exterior of a column foot, the peripheral edges of the annular rib plate are in horizontal seamless connection with the inner wall of the steel-plate-encased cylinder, and a rib plate hole is formed in the middle of the annular rib plate; a gap is reserved between the bottom end of the steel-plate-encased cylinder and the upper surface of the foundation; a plugging material is additionally arranged on the outer side of the gap; sleeve holes matched with grouting sleeve devices are formed in the annular rib plate; the edge of the steel plate cylinder, the annular rib plate, the plugging material and the upper surface of the foundation form a closed joint cavity; and the joint cavity is filled with a grouting material. The column foot joint and the construction method thereof have the advantages that the constraint effect on column foot concrete can be improved, the ductility level of the column foot joint can be improved, fixing tools for sleeves in the production process of a component can be omitted, the positioning precision of the sleeves of the prefabricated column can be improved, the structure is simple, and the construction is convenient.