A dynamic random access memory (DRAM) and an operation method thereof are provided. The DRAM includes a temperature sensor, a dynamic memory cell array, a control circuit, a plurality of power supply circuits and a power control circuit. The temperature sensor senses an operating temperature of the DRAM. The control circuit is coupled to a dynamic memory cell array, and accesses and manages the dynamic memory cell array. The power supply circuits powers the dynamic memory cell array and the control circuit. The power control circuit controls power outputs of the power supply circuits. When the DRAM enters the self-refresh mode, the power control circuit selectively switches between a low power control state and a normal power control state according to the operating temperature of the DRAM.