From the measurements of magnetization and specific heat, we constructed B-T phase diagrams of single-crystalline DyPd3S4 which is known to exhibit antiferroquadrupolar (AFQ) and antiferromagnetic (AFM) ordering at low temperatures. The phase diagrams are found to be highly anisotropic and reentrant, which are typical of rare-earth compounds exhibiting multipolar ordering. The crystalline electric field (CEF) scheme of Dy3+ in DyPd3S4 was deduced from the specific heat and magnetization measurements of the Y-diluted compounds Dy1-xYxPd3S4 (0.1 <= x <= 0.9) and discussed in detail. The CEF ground state was determined to be the orbitally-degenerated quartet 17670), and the overall splitting width was estimated to be about 104 K. No correlation was found between the anisotropy of To and that of the Zeeman splitting width of the ground quartet Gamma((1))(67).