Huynen Target Parameters(HTPs) and Optimum Polarizations(OPs) are two fundamental concepts in the polarization information processing field. According to the characteristic angle of HTPs, the graphical representation of OPs can be divided into three classes, needle shape, top shape, and the well-known fork shape, which has not been sufficiently discussed before. In this paper, OPs are derived based on the Kennaugh matrix. Then, the relationship between HTPs and OPs is revealed. On the basis of that, the polarization scattering characteristics of several typical structures are investigated. This paper aims to establish a clear concept about HTPs and OPs for radar polarimetry researchers.