The silicified membranes in the spin-column come from world-famous company. The results are reliable because of little variation among different filter carbidges. RNA selectively binds to silicified membrane in high concentrated salt solution, after a serial of elution- centrifuge steps to remove cellular metabolite and proteins etc. Finally total RNA is eluted from silicified membrane in low salt RNase-free water. The kit is designed for purifying RNA from all kinds of reaction system (such as, DNase digestion, proteinase digestion and RNA marker). The purified RNA with no any protein contamination, can be applied for Northern Blot, Dot Blot, mRNA Extracting, cDNA Synthesis, Primer Extension, mRNA differential Display etc. The amount of sample is up to 50μg.