The invention relates to a technical field of oil-gas field development and discloses a splicing tank. The splicing tank comprises a tank wall and a sac body with the upper end opened. The tank wall is spliced by at least two wall boards, the sac body is located in the tank wall, and the upper end of the sac body is fixed to the edge of the upper end of the tank wall. The splicing tank is reasonable and compact in structure and convenient to use. The tank wall is spliced by a plurality of splicing boards and the sac body is laid in the tank wall so that rapid installation can be achieved. Meanwhile, the splicing tank is convenient to detach and transfer, capable of being reused, short in construction period, low in cost, good in sealing performance and capable of avoiding use of reinforced concrete, reducing resource waste, construction cost and maintaining cost, protecting the environment and improving economical benefits and social benefits.