This chapter provides an in-depth exploration of the fundamental and analytical aspects related to the physical analysis of polymers. It begins with the molecular weight distribution conception and explores into various experimental techniques used for the molecular weight determination of polymers, including ebulliometry, viscometry, osmometry, end-group analysis, light scattering, and ultracentrifugation. The chapter then transitions to the concept of electrical conductivity in polymers, discussing both its theoretical foundation and practical measurement techniques for electrical and thermal conductivity. The latter half of the chapter focuses on the crystallinity of polymers, elaborating on their basic principles, structural implications through unit cells and Miller indices, and influence on material properties. Models such as the fringed-micelle and folded-chain models are described, along with the thermodynamics and kinetics of crystallization. The chapter concludes with a detailed discussion on the analysis of polymer crystallinity using X-ray diffraction (XRD), covering X-ray generation, the mechanism of XRD pattern formation, and analysis of polymer samples. Overall, this chapter offers a comprehensive understanding of key physicochemical properties critical to polymer science and technology.