The invention is applicable to the field of computer technology and provides a DRAM initialization method and a device thereof. The method comprises the following steps: address space of a DRAM is divided into N blocks, and N is an integer which is greater than 1; the DRAM undergoes bad block scanning according to the division result, and the scanning result is recorded into a preset data sheet; according to the record of the data sheet, the DRAM undergoes address remap, including: combining address continued non-bad blocks into a block region and acquiring starting address and capacity size of the block region; according to the division result, configuration files of operating system nucleus are modified so as to expand the nucleus space of receiving parameters; and the starting address and capacity size of the block region are transmitted to the nucleus so as to finish initialization of the DRAM. The address space of the DRAM undergoes remap to make an operating system normally operate on a DRAM with bad blocks. Thus, storage resource utilization rate is effectively raised.