Monoclinic LaPO4 and Fe doped LaPO4 have been prepared by the hydrothermal method in an acid aqueous solution. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectrum and X-ray photoelectron spectra are used to characterize the structure, morphology and composition of the samples. The pure LaPO4 sample shows paramagnetism at room temperature, but the Fe doped LaPO4 sample shows ferromagnetism with the coercivity of 166 Oe and saturated magnetization of 3.28 x 10(-2) emu/g, respectively. The magnetic mechanism of the Fe doped LaPO4 sample has been discussed according to the electron density of states calculation by using the Vienna ab initio simulation package. The results indicate that the origin of ferromagnetism is mediated by the double exchange mechanism, in which impurity bands are formed and partially occupied in the band gap of the LaPO4, and the exchange split is larger than the bandwidth of t(2g). (C) 2012 Elsevier B.V. All rights reserved.