The mechanisms underlying high-altitude hypoxia adaptation on the Qinghai-Tibet Plateau have been extensively studied, yet the role of alternative splicing in this process remains poorly understood. Yunnan’s vertical zoning with pig breeds distributed across varying elevations provides an excellent model for investigating hypoxic adaptation. Here, we examined three indigenous Yunnan pig breeds: Diannan small-ear pigs (DSE, 500 m), Baoshan pigs (BS, 1500 m), and Diqing Tibetan pigs (DT, 3200 m). Using PacBio Iso-Seq, we obtained comprehensive full-length transcriptomes from five tissues (heart, kidney, liver, lung, and spleen), identifying 51,774 transcripts, including 34,813 novel ones, and 74,843 Alternative Splicing (AS) events across 10,686 AS genes. Significantly, skipped exons (SE) were the predominant form of alternative splicing (AS) based on the reference dataset, whereas alternative first exons (AF) were the most frequent AS events in novel isoforms. We further identified five actin-binding genes (FHOD3, TNNC1, ACTN2, PDLIM5, and TNNI3) crucial for maintaining cellular structure and function under hypoxia, and five HIF pathway genes (PFKM, CAMK2D, PDHA1, TF, TFRC) with extensive alternative splicing variants, implicating their roles in regulating energy and iron metabolism for hypoxia adaptation. Differential alternative splicing (DAS) analysis identified numerous DAS events between high- and low-altitude pig breeds, including 3,816 events for BS vs. DT and 1,741 for DSE vs. DT. Furthermore, we identified six alternative splicing genes (AGO2, PDK1, ZNF12, FBLN1, CSF1, RRBP1), exhibiting significant differences in transcript usage across breeds, highlighting their regulatory importance in hypoxia adaptation. Our findings improve the genome annotation, deepen the understanding of hypoxia molecular mechanisms in pigs, and provide valuable insight into the genetic basis of high-altitude adaptation in other species.