The internal bond strength （IB） of boards made from three species of laccase-activated wood fibers （Pinus kesiya var. langbianensis, Liquidambar formosana and Cunninghamia lanceolata） was tested and compared. The experimental data indicated that under the same activating conditions, these activated wood fibers revealed different auto-adhesion strength, which was deemed by the authors to possibly be related to lignin contents of wood fibers. The optimum pH values for the activating reaction medium for the three wood species were all within the acidic range, though there are some slight differences among them.