Enrichment of eukaryotic mRNA with magnetic beads with Oligo (dT); The mRNA was randomly interrupted by adding Fragmentation Buffer; Using mRNA as template, the first cDNA chain and two strands were synthesized, and the cDNA was purified;The purified double-stranded cDNA was then end-repaired, A-tail was added and sequencing joints were connected, and AMPure XP beads were used for fragment size selection;cDNA library was obtained by PCR enrichment.