To improve the efficiency and accuracy of the dynamic spectrum data processing, the method of single-trial estimation was adopted. First, the rising edge of the whole band PPG was extracted, which was calculated by averaging superimposed collected photoelectric plethysmography (PPG) at all wavelengths as a template per single pulse; Second, this template was used to correct the rising edge of PPG at all wavelengths, and the difference of absorbance was calculate, and then a single-trial DS was obtained; finally, the single-trial DS which contained the gross error under the 3σ criterion was removed, and then the remaining superimposed single-trial DS was averaged as the final output of the DS. Data measured from 10 volunteers were compared with the results of the extraction in frequency domain: the correlation coefficient distribution of the DS from the same finger of the same individual was improved from 0.006 775 to 0.000 384 0; the correlation coefficient distribution of the DS from the different fingers of the same individual was improved from 0.013 93 to 0.002 205, whereas the differences of DS between different individuals were significantly increased. The results show that the method of single-trial estimation can get the DS data more quickly with high quality, and accelerate the process of DS put into practical application.