TissueScope is a cross-species bulk RNA-seq brain atlas designed for large-scale transcriptomic comparisons across species and tissues, allowing users to explore evolutionary gene expression patterns and tissue-specific transcriptomics. It concludes 293 species spanning 147 fishes, 6 amphibians, 109 mammals, 11 reptiles, and 20 birds. TissueScope offers key functional modules: sPandora & ePandora, allowing single-gene and gene-set expression analysis; GeneLists, providing access to differentially expressed gene lists for specific tissues; and TimeTree, which visualizes phylogenetic relationships among species for evolutionary insights. For bulk RNA-seq data preparation, Trinity was used to assemble transcripts from filtered data, addressing the challenge of missing reference genomes for many studied species. The assembly process was performed with a maximum memory allocation of 200 GB while maintaining default parameters. To refine the assembled transcripts, cd-hit-est was applied with a 90% similarity threshold, removing redundant sequences while retaining the longest representative transcripts. Subsequently, TransDecoder was used to identify protein-coding genes and predict corresponding protein sequences under default settings.