Objective To compare the difference between shade guide and spectrophotometer used by evaluating treatment total effective rate after tooth bleaching. Methods 59 maxillary central incisors bleached with 35% hydrogen peroxide. Teeth color measured with Vita classical shade guide and CM-700d spectrophotometer before and after bleaching. Total effective rate calculated by the evaluation standard of curative effect and analyzed for X2 test by SPSS17.0 statistical software. Results The total effective rate of bleaching was statistically difference between shade guide and spectrophotometer, P=0.031. The total effective rate of bleaching with spectrophotometer was higher than shade guide, 97%, 87% respectively. Conclusion The accuracy of color measurement with spectrophotometer is higher than visual colorimetric. And more fully describes the change of teeth color. Thus spectrophotometer should be gave priority to the assessment of bleaching effect.