Rainbow trout is a typical cold-water fish, with the intensification of global warming, high temperatures severely restrict the development of aquaculture in summer. Understanding the molecular regulation mechanisms of rainbow trout in response to heat stress will be salutary to alleviate heat stress-related damage. In the present study, we performed transcriptome analysis of liver tissues in rainbow trout under heat stress (24?) and control (18?) conditions to identify induced lncRNAs and pathways by heat stress. More than 658 million clean reads and 5,916 lncRNAs were identified from six liver libraries. A total of 927 novel lncRNAs were generated and 428 differentially expressed lncRNAs were screened through stringent thresholds. The RNA-seq results were verified by RT-qPCR. In addition, the regulatory network of important functional lncRNA-mRNA were constructed. GO and KEGG enrichment analysis of target gene of differentially expressed lncRNAs were performed. Many target genes involved in maintaining homeostasis or adapting to stress and stimuli were highly induced under heat stress. Several important regulatory pathways were involved in heat stress, including thyroid hormone signaling pathway, PI3K-Akt signaling pathway, estrogen signaling pathway, etc. This result broadens our understanding of lncRNA associated with heat stress and provides new insights into lncRNA-mediated regulation of rainbow trout heat stress. Overall design: liver tissues of rainbow trout under heat stress (24C, HS, n=3) and control (18C, CG, n=3) conditions to identify induced lncRNAs