Abstract: In order to study the biosynthesis pathway of esculentoside A, the Illumina HiSeq 4000 highthroughput sequencing method was used to analyze the transcriptome of Phytolacca americana seedlings. The 9.60 Gb clean data were obtained after the transcriptome of P. americana assembled by Trinity software. The total 63 957 unigenes were obtained after assembly and the average length was 988.82 bp, among them 24 517 unigenes (38.33%) were annotated in the public databases Nr, Swiss-Prot, COG, KOG, Pfam, GO and KEGG. According to the assignment of KEGG pathway, 53 unigenes were involved in terpenoid backbone biosynthesis and 8 unigenes involved in triterpenoid biosynthesis. Additionally, there were 417 unigenes assigned to other secondary metabolic pathways in P. americana. The post-modification enzyme genes involved in the esculentoside A biosynthesis were also analyzed in the transcriptome of P. americana. The results indicated that 130 unigenes may have the function of CYP450 which was involved in oxidation/hydroxylation modification of P. americana secondary metabolites. Furthermore, 46 unigenes had the function of glycosyltransferase UGT. The transcriptome data of P. americana laid a foundation for studying the biosynthesis pathway of esculentoside A and other secondary metabolites, and also provided theoretical basis for formation of medicinal materials quality.