Semiconductors are crucial components of electronic devices that influences almost every aspect of modern society. Efforts from generations have been put into this field, especially in searching for and studying new semiconducting materials. Nowadays, silicon is the most critical element for fabricating most electronic circuits. But along with the development of manufacturing technology, the Si transistors have approached to their limits and thus hinders the development of new Si-based devices. The 2D semiconductors are believed to be an alternative to Si for next-generation semiconductor devices because of their novel properties. Therefore, the study of 2D semiconductors is very meaningful for new devices. In my thesis, we focuses on the optical properties of 2D material heterostructures and the WS2 monolayer integrated with plasmonic structures. First, the CVD-grown twisted bilayer WS2 and the mechanically-stacked WS2/perovskite heterostructure were studied. Then the surface plasmon enhanced PL and Raman scattering of a WS2 monolayer were investigated. In addition, technical skills such as obtaining WS2 monolayers, preparing plasmonic metastructures, and transferring 2D materials have also been discussed. And we then study the optical properties of plasmonic structures and their hybrid system with WS2 by measuring and analyzing the spectra of PL, Raman, reflection/absorption, and angle-resolved reflection/absorption. At last, we introduce numerical simulations (FDTD) to understand and confirm our results from theoretical aspects. Although our results enrich the content of 2D TMDs in photonics and optoelectronics, challenges still remain in commercializing 2D TMD photonic and optoelectronic devices.