Single crystal bar of Pr1/2+ySr1/2-yMnO3 was successfully prepared by the floating zone growth method, which shows evident anisotropic properties, indicating good quality of crystal. Magnetic measurements were performed on several chips taken from the crystal and three kinds of different magnetic behaviors were found at low temperatures for the half doped Pr1/2+ySr1/2-yMnO3 system. The results reveal that slight inhomogeneous element distribution of the crystal obtained by floating zone growth method may be inevitable, but even a slight change of Sr ratio does affect the physical properties of the sample ultimately. Therefore, doped rare-earth manganites is a system strongly depends on the ratio of Mn3+/Mn4+, i.e., the content of the divalent alkaline-earth element. (C) 2012 Elsevier B.V. All rights reserved.