The method to determinate the concentration of TiO_2in bleaching bamboo fiber is reported. Sample is nitrified with burning and dissolved in mix acid. Spectrophotometric determination with H₂O_2is the analysis method. Optimum analytical conditions are studied.Ascorbic acid is shelter reagent of Fe³⁺ and Cu²⁺,H₂O_2is displaying-color reagent. Detection wavelengh is 410nm. The detection limit of trace TiO_2can amount to 0.05~3.20mg/L. The function of standard curve is y=0.0851x+0.0093(R²=0.9992). The average recovery ratio is 98.5% upwards, and relative standard deviation (RSD) is 0.58%.