The invention belongs to the field of molecular biology and relates to a method for rapidly extracting a plant miRNA (micro ribonucleic acid). The method comprises the following steps: taking a plant material, grinding the plant material by liquid nitrogen and mixing the ground plant material with a CTAB (cetyltrimethyl ammonium bromide) extract; after carrying out water bath, carrying out water saturation and phenol/chloroform extraction; precipitating by ethanol to obtain total nucleic acid; after dissolving the total nucleic acid by guanidinium isothiocyanate, carrying out phenol/chloroform extraction twice; carrying out precipitation of a large RNA segment by PEG8000 (polyethylene glycol 8000) and sodium chloride; and taking supernatant to obtain the miRNA. The method adopts a simple process; proteins and genomes DNA (deoxyribonucleic acid) are removed by phenol/chloroform and guanidinium isothiocyanate; the large RNA segment is removed by a PEG8000 and sodium chloride precipitating method; the defect of excessively losing the miRNA due to LiCl precipitation is overcome; experiment cost can be greatly reduced; more choices are provided for researchers in the actual work; and the extracted miRNA has high quality, can meet the requirements of research on an RT-PCR (reverse transcription-polymerase chain reaction), miRNA and the like and can be well used for subsequent molecular biological experiment research.