Abstract: This paper deals with a technology for raising the retcntion rate during the strengthening of wet-processed fiberboard with TPFR(Tannin-Phenol-Formaldehyde Resin).Based on the results of three-wave-length UV spectrum analysis and orthogonal test,an improved processing method allowing optimum retention is proposed.the new processing technology raises the retention rate by more than 27% on the average.