Abstract: To investigate the effects of different preservation treatments on the quality of winter jujube (Ziziphus jujuba Mill. cv. Dongzao) during storage at ambient temperature, Huanghua winter jujubes were used as test material and treated with 1-methylcyclopropene (1-MCP), chitosan (CTS), nano-selenium (nano-Se), 1-MCP + CTS, and 1-MCP + CTS + nano-Se, with water soaking serving as the control group. The jujubes were stored for 21 days at ambient temperature (22 °C ± 1 ℃) and a relative humidity of 60%-70%, and relevant quality parameters were measured to identify the most suitable preservation method. The results indicated that, compared with other treatments, the 1-MCP + CTS + nano-Se treatment demonstrated a significant advantage in delaying the senescence of winter jujube during storage. This treatment not only delayed the onset of respiratory and ethylene peaks, but also increased peroxidase (POD) activity and glutathione (GSH) content, while reducing the accumulation of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA). Furthermore, it maintained higher levels of pectin, cellulose, and hemicellulose in the cell walls of winter jujubes, mitigated the decline in firmness and soluble solids, and significantly reduced the fruit rot rate, weight loss rate, and reddening index. Additionally, the 1-MCP + CTS + nano-Se treatment boosted phenylalanine ammonia-lyase (PAL) activity and increased the flavonoid and selenium contents. This effectively achieved selenium biofortification and improved functional quality while delaying fruit senescence. In summary, the 1-MCP + CTS + nano-Se treatment is proven to be an effective and innovative preservation technique for winter jujubes, providing novel theoretical and technical insights for the postharvest storage research of winter jujubes.