Abstract: In order to establish a method for nondestructively determining the coating rate of paper-making process reconstituted tobacco, an X ray areal densitometer was used to determine the grammage of different reconstituted tobacco samples, and a linear regression model reading grammage and measured grammage was established. The coating rate was obtained by calculating the grammage of base sheet and finished reconstituted tobacco via the established model. The calculated coating rate was compared with that by the oven method. The results showed that:1) The determination coefficients (R²) of the model for both reconstituted tobacco and base sheet were higher than 0.9. The relative error between the grammages calculated with the model and measured with the national standard method was less than 2%. 2) Under different moisture contents, the regression models for reconstituted tobacco samples of the same brand were similar. 3) The coating rates measured by the X ray method and the oven method showed good consistency, p>0.05 in paired t test, and the intra-group correlation coefficient was 0.989. 4) The intra- and inter-day RSDs were 0.133%-0.496% and 0.223%-0.486%, which suggested that X ray method featured good repeatability and precision.