Objective: To explore the preservative effect of soybean protein isolate-tea tree oil Pickering emulsion (EM) on trawl-net hairtail stored at 4 °C. Methods: The chemical composition of tea tree oil was analyzed by gas chromatography-mass spectrometry (GC-MS). Pickering emulsion (EM) loaded with tea tree oil was prepared using soybean protein isolate as the emulsifier. The pH， total volatile basic nitrogen (TVB-N)， total viable count (TVC)， and sensory indicators of trawl-net hairtail were monitored during storage at 4 ℃. Microbiome analysis was conducted to examine the dynamic changes in the bacterial community. Results: GC-MS analysis identified terpinolene(21.63%) and 4-terpineol (12.16%) as the main active components of tea tree oil. EM treatment significantly delayed the increase in sample pH. The TVB-N value of the 25 μL/mL EM group reached 39.81 mg/100 g on day 8， exceeding the spoilage threshold of 30 mg/100 g， which was 4 days later than the control group (36.19 mg/100 g on day 4). EM also inhibited TVC growth， achieving an 81.05% inhibition rate on day 8， and maintained better sensory quality than the control group. Microbiome analysis showed that EM could maintain the Shannon diversity index and delay the succession of dominant bacterial communities， significantly reducing the relative abundance of Psychrobacter (81.24%) compared to the control group (98.52%). Conclusion: EM prolongs the shelf life of trawl-net hairtail to 8 days by modulating the microbial community structure and inhibiting the growth of spoilage bacteria， providing a theoretical basis for the development of green preservation technologies for aquatic products.