Abstract： The crystal of cerium pentaphosphate with composition CeP5O14 belongs to monoc-linic system. The lattice parameters are as follows:α=8.797?, b=9.074?, c=13.124?, β=89°36′, Z=4. The space group is C2h5-P21/c. The diffraction data were collected using PW-1100 four-circle diffractometer. The number of independent diffraction data amounts to 2051. The structure is solved by heavy-atom method. Structure parameters were refined by full-matrix and block-diagonal least squares to a final R = 0.097. The result of structure analysis establishes that the structure is built up with discrete anionic ribbons linked by the cations in a complicated way. The polyhedral coordination of slightly distorted square antiprism is formed by eight oxygen atoms surrounding the Ce-cation. The shortest distance between two Ce ions is 5.967?.