The invention discloses a proximate analyzing method for coal quality base on multivariate linear regression, The invention is characterized in that a set of samples with known proximate analysis index values is used, plasma spectrum data is obtained by detection of a coal quality on-line analysis system of LIBS (Laser-Induced Breakdown Spectroscopy), the proximate analysis of fire coal samples to be measured by a multivariate linear regression correlation of each proximate analysis index value are respectively established, the characteristic spectral line strength which has substantial contribution to proximate analysis index values is respectively introduced through the established multivariate linear regression correlation to obtain the proximate analysis results. According to the invention, the spectral line information of correlative elements which has substantial contribution to each proximate analysis index is comprehensively utilized, the process for analyzing the index by fire coal proximate analyzed by the LIBS can be simplified, and the speed and the accuracy of the quantitative analysis can be raised.