The quality of NIR quantitative detection models is influenced by many factors such as spectral quality and modelling methods.In this study,the effect of spectral acquisition conditions and modelling set selection on the models were investigated using the Chinese and Tibetan herb Gentiana straminea Maxim..The results showed that the scan times,resolution and sample loading height did not have significant effects on the quality of the spectra.As the sample size of the modelling set increased,the model quality increased firstly,then decreased and stabilized at last.The model quality was found independent of the sample set content.And the effect of SD values on the model indicated that the sample size and the concentration range of the sample had great influence on the model quality.It could be seen that when making the selection of the modelling set samples,the sample concentration range should be large,whereas a larger sample size was not better.And the modelling can be carried out by converting the content units when content was too low.