RNA-Seq (RNA sequencing) is a sequencing technique which uses next-generation sequencing (NGS) to reveal the presence and quantity of RNA in a biological sample at a given moment, analyzing the continuously changing cellular transcriptome. RNA library preparation includes cDNA (complementary DNA) synthesizing and adaptors ligation which transform RNA into cDNA libraries. Yeasen upgraded the pre-version RNA library prepartion kit and merged the previous RNA library prep kit suitable for Illumina and MGI into one kit compatible with dual sequencing platform. Moreover, The new version RNA library prep kit can be used non-strand specific and strand specific RNA libraries.