This thesis focuses on high-mass star formation by using infrared and sub-millimeter data mainly from the Spitzer Space Telescope and Mopra Telescope MALT90 Survey data archives. The first part is a photometric study of massive star-forming regions W49, W51, W43 in the Galaxy to investigate the census of Young Stellar Objects (YSOs) membership by using color-color and color-magnitude relations. YSO catalogs with thousands of sources are generated for these regions. The second part is a spectroscopic investigation of high-mass clumps. MALT90 Survey data was used to investigate different stages of star formation. Physical and chemical properties of these clumps were determined. The spatial distribution of lines, their profiles, and column densities indicate that these sources are at very early stages of star formation. There are several interesting sources among them need further investigation with high sensitivity and high spatial resolution.