The invention provides a cold storage tank. The cold storage tank comprises a tank body which opens upwards, a box body used for storing to-be-stored objects, and at least one cold storage block, wherein the inner circumferential wall of the tank body is provided with at least one positioning slot which extends vertically, and the upper end of each positioning slot opens upwards to form a notch; a circumferential wall plate of the box body is provided with at least one inserting part, and when the box body is placed into the tank body, the inserting parts enter the positioning slots from the notches to enable the box body to be fixed in the tank body; at least one storage gap is defined between the circumferential wall plate of the box body and the inner circumferential wall of the tank body; and each cold storage block is inserted into the corresponding storage gap. According to the cold storage tank, the to-be-stored objects and the cold storage blocks can be conveniently and quickly placed into the tank, so that cold loss is reduced; and the refrigerating effect of the cold storage blocks on the to-be-stored objects can be improved.