Abstract:620 Chinese hardwood species were investigated into their xylem crystalliferous cells by means of SEM and light microscopy. 231 wood species from114 genera and 44 families were found containing crystalliferous cells in theirxylem paranchyma cells, 7 types of crystals were classified and described inthe present paper. They were prismatic, acicular, raphide, styloid or elongate, crystal sand, small cubic and druse, of which types, size and locationwere proved to be of diagnostic value. The occurrence of crystalliferous cellsin xylem is common to many Chinese hardwood species, specially tropic species.