The invention discloses a method and device for improving the matching reliability and measurement precision of a spectrum curve in OCD measurement equipment. The method comprises the steps: carrying out the sensitivity analysis of theoretical spectrums of all to-be-measured structure parameters at full-wavelength points, and obtaining the sensitivity wavelength distribution; carrying out the normalization processing of the sensitivity wavelength distribution of all to-be-measured structure parameters; flexibly configuring a normalized weighting coefficient, and carrying out the normalized processing of the sensitivity wavelength distribution after normalization; setting a matching weighting coefficient in the matching process of a theoretical spectrum and a measurement spectrum, and carrying out the estimation optimization operation of the theoretical spectrum and the measurement spectrum, so as to judge the matching degree of the theoretical spectrum and the measurement spectrum. Therefore, the method achieves the optimized design of matching estimation, and achieves the improvement of the fitting value precision of the to-be-measured structure parameters.