The invention relates to the field of biomedicine, in particular to a real-time fluorescent quantitative RT-qPCR method for directly detecting circulating microRNA (miRNA) in serum or plasma without extracting nucleic acid. The method includes: S1: lysing exosomes and miRNA protein complexes in serum or plasma, and centrifuging to obtain crude circulating miRNA extracts; S2: miRNA tailing and reverse transcription; S3: RT-qPCR quantitative detection. In the miRNA direct fluorescent quantitative RT-qPCR amplification method [Direct S-Poly(T) Plus, DSPP for short] of the present invention, nucleic acid does not need to be extracted, and the Poly(A) tailing and reverse transcription of miRNA will be in one reaction system Synchronously completed, easy to operate and shorten the time, the preparation of cDNA can be completed within 95 minutes. Compared with the stem-loop method, the sensitivity of this technical system is increased by tens or even hundreds of times, and a very simple, sensitive, efficient, fast and cheap miRNA detection technical system has been established. This technical system is especially suitable for clinical application promotion and detection of miRNA from biological fluid samples with low miRNA abundance.