The invention relates to the technical field of construction of immersed tube tunnels, in particular to a dry-dock system for casting full cross-section precast concrete. An immersed tube precast yardbottom plate structure used for precasting an immersed tube; a reaction tank and a first base are arranged on the immersed tube precast yard bottom plate structure; a reaction part connected with thelower part of an outer side template is arranged in the reaction tank; and the reaction tank is reserved, when the dry-dock system is used, through the arrangement of the reaction part connected withthe lower part of the outer side template, the reaction tank can support the lower part of the outer side template by a lateral acting force applied to the lower part of the outer side template in casting, a connecting piece connected with the middle of the outer side template is arranged on the first base, and through the arrangement of the first base, when the dry-dock system is in use, throughthe connecting piece connected with the middle of the outer side template, the first base can support the middle of the outer side template by a lateral action force applied to the middle part of theouter side template. The dry-dock system adopting the structure solves the problem that an existing dock floor structure cannot be supported by arranging a template, and the lateral supporting forceis provided for the middle and the lower part of the outer side template through the first base and the reaction tank.