In this paper, starting from analyzing the normal triple prism and other polarizing elements, we have studied both theoretically and experimentally the polarization properties of two novel prism resonators used for slab lasers, i. e., the coaxis resonator with a compound total internal reflection (TIR) prism and a mirror, half o f which has reflectivity R and the other half has a high-reflection coating (R/HR mirror), and the folded resonator with a compound TIR prism, a normal triple prism and a R/HR mirror.