Abstract: In order to reduce the physicochemical index fluctuation of and foreign matter content in raw material of paper-making reconstituted tobacco, promote metering precision and improve working environment, an on-line blending and clean feeding system was designed. The system comprises a cylindrical sieve and a metal detector for removing foreign matters, a stem thresher for pretreating the stems longer than 3 cm, a raw material blending tank, and a pneumatic tube conveyor. The material blended by the new blending system was compared with that blended by a blending silo, the results showed that:1) The on-line blending system reduced the fluctuations of stem size, total sugar in stem and total sugar in tobacco dust between batches from 17.21% to 2.99%, from 8.85% to 2.08%, and from 18.21% to 2.60%, respectively. 2) The metering error of material decreased from 5.75% to 0.85%, the effective rejection rate of foreign matters reached 98.5%. The designed system provides technical supports for promoting the process stability and metering precision in reconstituted tobacco making.