In this project, rRNA in total RNA was removed by ribosomal RNA removal kit, and ion interruption was used to break the RNA to a fragment of about 300bp in length. The length of 300bp was chosen because the length of the junction is fixed, if the length of the interrupted fragment is shorter, it will lead to a high proportion of the junction sequence, which will reduce the proportion of valid data; if the length of the interrupted fragment is longer, it will be unfavorable to the generation of clusters in the process of on-line sequencing. The first strand of cDNA was synthesized using RNA as template with 6-base random primer and reverse transcriptase, and the second strand of cDNA was synthesized using the first strand of cDNA as template. After RNA extraction, purification and library construction, the libraries were subjected to paired-end (PE) sequencing using Next-Generation Sequencing (NGS) based on the Illumina HiSeq sequencing platform.