A NEMS device structure and a method for forming the same are provided. The NEMS device structure includes a first dielectric layer formed over a substrate, and a first conductive layer formed in the first dielectric layer. The NEMS device structure includes a second dielectric layer formed over the first dielectric layer, and a first supporting electrode a second supporting electrode and a beam structure formed in the second dielectric layer. The beam structure is formed between the first supporting electrode and the second supporting electrode, and the beam structure has a T-shaped structure. The NEMS device structure includes a first through hole formed between the first supporting electrode and the beam structure, and a second through hole formed between the second supporting electrode and the beam structure.