A NEMS device structure and a method for forming the same are provided. The NEMS device structure includes a substrate and an interconnect structure formed over the substrate. The NEMS device structure includes a dielectric layer formed over the interconnect structure and a beam structure formed in and over the dielectric layer, wherein the beam structure includes a plurality of strip structures. The NEMS device structure includes a cap structure formed over the dielectric layer and the beam structure and a cavity formed between the beam structure and the cap structure.