A fabricating method of a DRAM structure includes providing a substrate comprising a memory array region and a peripheral region. A buried gate transistor is disposed within the memory array region, and a planar gate transistor is disposed within the peripheral region. Furthermore, an interlayer dielectric layer covers the memory array region, the buried gate transistor and the planar gate transistor. Then, a capping layer of the planar gate transistor and part of the interlayer dielectric layer are removed simultaneously so that a first contact hole, a second contact hole and a third contact hole are formed in the interlayer dielectric layer. A drain doping region of the buried gate transistor is exposed through the first contact hole, a doping region of the planar gate transistor is exposed through the second contact hole, and a gate electrode of the planar gate transistor is exposed through the third contact hole.