The preliminary study on purple sandstone in Shilin, Yunnan Province showed that the purple sandstone had rich nutrients, trace amount of organic matters and humic acids, and its natural water content was 3%, pH was weak acidic, with no excessive arsenic(As), hydrargyrum(Hg) and other heavy metal elements. Sound seedlings could be produced in the medium with different percentages of purple sandstone, expanded perlite and various organic fertilizers, and the cost of nursery was reduced. Compared with Honghe commercial medium, the application of new medium could reduce cost by 168.30 yuan/ha. Therefore, the purple sandstone is ideal medium material for tobacco seedling float system.