 1. Abstract electromagnetic EM, wave-absorbing materials play a crucial role in modern society for their multifunctional applications in military stealth and the incoming 5G smart era. 2. Dialectric loss EM wave absorbers and underlying loss mechanism investigation are essential to understand EM wave attenuation behaviors of materials and guide novel dielectric loss material design. However, current research focuses more on material synthesis rather than in-depth mechanism study. 3. Comprehensive views toward dielectric loss mechanisms including interfacial polarization, dipolar polarization, conductive loss, and defect-induced polarization are provided. New dielectric loss mechanism regulation strategies instead of regular components compositing are summarized to provide inspiring thoughts toward simple and effective EM wave attenuation behavior modulation. This article was authored by Mingqin, Li Mingzhuang, and Hongjing Wu. We are article.tv, links in the description below.