As shown in the diagram, the system is consisted of a rotating drum, feeding port and film deposition part for the feed solution, and a scraper to scrape off the dried material. Steam is introduced into the material to heat the surface of the drum as the evaporation front. The feed solution is supplied to the surface of the drum, evaporates and concentrates, and at the same time adhered to the surface to form a thin film to quickly evaporate and dry. The dried non-volatile material is continuously scraped off the surface of the drug by the scraper, forcing the heat transfer surface to renew.