The on-line detection of incoming-coal property is of great significance to optimize the boiler operation and promote the development of intelligent power plant. In recent years，laser induced breakdown spectroscopy has been widely applied in coal property detection，due to its powerful on-line detection. Based on the operation of coal transporting system in the power plant，an on-line detection scheme for LIBS direct measurement of raw coal property on conveyor belt is proposed to meet the basic needs of online detection of incoming-coal property. To validate the feasibility of the detection scheme，the simulation platform for incoming-coal conveyor belt and the LIBS system were set up. 34 actual raw coal samples are placed on the conveyor belt as measurement objects to carry out continuous LIBS measurements and obtain spectral data. According to the spectral characteristics obtained from direct measurement of raw coal，CN388.176 nm is determined as the characteristic peak used in spectra selection and internal standard. Effective spectra selection，spectra averaging and internal standard method are used to reduce the adverse effects of invalid spectra and spectral signal fluctuations. Combined with the partial least squares(PLS）modeling method，the quantitative analysis models of coal property were established，and the good measurements of coal ash，volatiles and calorific value were achieved. The regression coefficient R2 of the ash，volatile，and calorific value are 0.98，0.97，and 0.97，respectively. The root mean square error of the prediction set are 1.33%，1.03%，and 1.11 MJ/kg，the mean absolute errors are 1.24%，0.97% and 0.88 MJ/kg，respectively. The results validate the feasibility of LIBS directly measuring raw coal quality on the conveyor belt and provide power plants a feasible scheme for online analysis of coal property.