Chrysanthemum-shaped celestite is a diagenetic nodule widely distributed in the Permian Chihsia Formation of South China. As precipitated in the very early diagenesis and replaced by subsequent diagenesis, most of the celestite nodules are pseudomorphs dominantly composed of calcite, chalcedony and minor dolomite. This paper deals with the establishment of a replacement succession in the pseudomorph and the evolution of related diagenetic environments. The replacement initiated in very early diagenesis by fine cloudy calcite, followed by length_slow chalcedony and fine granular calcite. The last two components originated respectively from an episode of chalcedony veining and a calcite veining. Celestite was also noted replaced directly by chalcedony. These replacements took place in fluids rich in silica and Mg2 , revealed by microprobe analyses on the replacement calcite and the occurrence of length-slow chalcedony. Chert nodules and sepiolite in the host rock were contemporary. Late replacements include euhedral calcite crystals in the chalcedony and coarse granular calcite that stemmed from an episode of calcite veining, resulting from diagenetic fluids with relative low Mg2+ /Ca2+ ratio.