A frequency-adjusting circuit, comprising: a temperature-sensing module configured to measure temperatures of a plurality of DRAM chips; and a computing module coupled to the temperature-sensing module and configured to determine a refresh frequency for the plurality of DRAM chips; wherein the computing module is configured to compare the temperatures of the plurality of DRAM chips measured by the temperature-sensing module to determine a first temperature, to compare previous temperatures of the plurality of DRAM chips to determine a second temperature, and to determine the refresh frequency based on the first temperature and the second temperature, wherein the computing module includes a first comparing unit coupled to the temperature-sensing module and configured to compare the temperatures of the plurality of DRAM chips to obtain the first temperature, which is a highest temperature of the temperatures of the plurality of DRAM chips, wherein the computing module further includes a second comparing unit configured to compare the previous temperatures of the plurality of DRAM chips to obtain the second temperature, which is a highest temperature of the previous temperatures of the plurality of DRAM chips, wherein the computing module further includes: a first computing unit coupled to the first comparing unit and the second comparing unit, and configured to obtain a first temperature difference based on the first temperature and the second temperature; a third comparing unit coupled to the first computing unit, and configured to compare the first temperature difference with a first preset temperature difference; and a selection unit coupled to the first comparing unit, the second comparing unit and the third comparing unit, and configured to obtain a third temperature based on results of a comparison between the first temperature difference and the first preset temperature difference, wherein when the first temperature difference is less than the first preset temperature difference, the third temperature is determined to be the same as the second temperature, and when the first temperature difference is equal to or greater than the first preset temperature difference, the third temperature is determined to be the same as the first temperature, wherein the computing module further includes a second computing unit coupled to the selection unit, and configured to compare the third temperature with a preset temperature set to determine the refresh frequency. a temperature-sensing module configured to measure temperatures of a plurality of DRAM chips; and a computing module coupled to the temperature-sensing module and configured to determine a refresh frequency for the plurality of DRAM chips; wherein the computing module is configured to compare the temperatures of the plurality of DRAM chips measured by the temperature-sensing module to determine a first temperature, to compare previous temperatures of the plurality of DRAM chips to determine a second temperature, and to determine the refresh frequency based on the first temperature and the second temperature, wherein the computing module includes a first comparing unit coupled to the temperature-sensing module and configured to compare the temperatures of the plurality of DRAM chips to obtain the first temperature, which is a highest temperature of the temperatures of the plurality of DRAM chips, wherein the computing module further includes a second comparing unit configured to compare the previous temperatures of the plurality of DRAM chips to obtain the second temperature, which is a highest temperature of the previous temperatures of the plurality of DRAM chips, wherein the computing module further includes: a first computing unit coupled to the first comparing unit and the second comparing unit, and configured to obtain a first temperature difference based on the first temperature and the second temperature; a third comparing unit coupled to the first computing unit, and configured to compare the first temperature difference with a first preset temperature difference; and a selection unit coupled to the first comparing unit, the second comparing unit and the third comparing unit, and configured to obtain a third temperature based on results of a comparison between the first temperature difference and the first preset temperature difference, wherein when the first temperature difference is less than the first preset temperature difference, the third temperature is determined to be the same as the second temperature, and when the first temperature difference is equal to or greater than the first preset temperature difference, the third temperature is determined to be the same as the first temperature, wherein the computing module further includes a second computing unit coupled to the selection unit, and configured to compare the third temperature with a preset temperature set to determine the refresh frequency.