The present invention discloses a tropical plant polysaccharide and polyphenol small RNA extraction method, which comprises: sampling tropical plant leaves, freezing in liquid nitrogen, and storing at a temperature of -80 DEG C; preparing small RNA extraction reagents, wherein the reagents comprise a CTAB lysis buffer solution, a PEG8000 precipitation buffer solution, an EDC cross-linking buffer solution, a miRNA Northern blotting hybridization buffer solution, 7% dPAGE, and Washing Buffer; according to small RNA extraction pretreatment, Trizol extraction, fractional precipitation of high molecular weight RNA, and small RNA precipitation, extracting small RNA; according to 17% dPAGE separation, trarsmembrane and cross-linking, miRNA hybridization and washing of membrane, small RNA hybridization and washing of membrane, and exposure and storage, achieving RNA hybridization; carrying out miRNA stem-loop RT-PCR amplification; and carrying out extraction and detection analysis on polysaccharide and polyphenol plant small RNA. According to the present invention, the defects in the current plant small RNA extraction method are overcome, characteristics of fastness, stability and easy operation are provided, rapid extraction and detection analysis can be performed on miRNA and siRNA, and broad application prospects are provided.