The invention discloses a method for extracting total ribonucleic acid (RNA) from paraffin-embedded tissues, which is an improvement method provided on the basis of a kit. The method comprises the following steps: deparaffinating, digesting, extracting and purifying. By adopting the method, the RNA in a tissue sample stored by being embedded by paraffin can be extracted, wherein, the longest storage time reaches up to 6 years; the RNA is analyzed by a nucleic acid trace tester and an internationally recognized Agilent 2100bioanalyzer; the extraction concentration is 211-3116ng / mu l, and the extraction purity is A260 / 280:1.75-2.04, which are all very ideal; and the expression research of microarray high-abundance genes of qRT-PCR and miRNA in mRNA and miRNA level can be carried out, which provides an experimental basis for developing a large amount of research on formalin fixed paraffin-embedded (FFPE) genes, and has wide application value.