This study explored the transcriptome differences in Fasciola hepatica at different developmental stages and identified functional genes related to growth and development during juvenile stages. DNBSEQ eukaryotic strand-specific transcriptome resequencing technology was used to sequence the transcriptomes of Fasciola hepatica eggs, juveniles, and adults. Additionally, the genes that were highly expressed during the juvenile stage were validated using qRT-PCR. The Q20 values of all three phases of sequencing were above 98%, and the Q30 values were above 94%. The differentially expressed genes (DEGs) in pairwise comparisons were analyzed by GO functional classification and the KEGG pathway database. Many immune-, growth-, and development-related pathways were found, which might be related to cell proliferation, development, and host immune evasion by Fasciola hepatica. In addition, five DEGs with high expression levels during the juvenile stage were identified: Cathepsin B, Glutathione S-transferase mu, heat shock protein 67B2, Kunitz-CH, and Legumain. Validation analyses revealed that these genes play key roles in maintaining normal growth, development, and immunological processes in liver Fasciola hepatica. RNA-seq was used to analyze the biological characteristics of the DEGs at different developmental stages concerning GO functional classification and KEGG metabolic pathways. Five DEGs with high expression during the juvenile stage were identified. These genes are related to the growth, development, and immune function of Fasciola hepatica, which provides a theoretical basis for subsequent research on the proteomics of Fasciola hepatica and the screening of candidate genes for early diagnosis.