The invention relates to a portable frozen box, which comprises a box body, a thermal insulation cover and a thermal insulation layer. A freezing layer is arranged inside the thermal insulation layer; a refrigerant is filled in the freezing layer; the interior of the freezing layer is provided with a freezing chamber; and the refrigerant is prepared by mixing ice and salt according to a certain ratio. The portable frozen box also comprises a division plate which is an independent circular division plate, wherein the inner diameter of the division plate is equal to or slightly more than the external diameter of the freezing chamber; the external diameter of the division plate is equal to or slightly less than the inner diameter of the freezing layer; the division plate is embedded in the freezing layer and is made of a brittle material; the ice and the salt are granular and are divided into an upper layer and a lower layer through the division plate to be arranged inside the freezing layer; and during use, the division plate is broken by shaking the frozen box so as to make the ice and the salt contacted and mixed. The portable frozen box is realized by the technology for arrangingthe freezing layer and the division plate arranged inside a common thermal insulation box, is rapid in refrigeration effect, low in cost and light in weight, and is an innovative product in the refrigeration industry; and the refrigeration effect of the frozen box is easy to keep and convenient to change.