Abstract: By comparing the models that were established by different spectra band, the results showed that the firmness model establishing under the 643.26～954.15nm spectrum was superior to the other two models. Methods of eliminating unusual samples and main components analyze were used to optimize the models. The firmness model results:correlation coefficient of calibration and RMSEC were 0.970 and 0.124. The prediction residual distribution results indicated that the models were stable and fulfilled the requirements of practical application, the optimal predictive scope of firmness model was 2～15kg/cm2.