Abstract: 【Objective】This study was conducted to investigate the effects of different levels of salt and alkalinity in the soil on the growth and photosynthetic characteristics of the hybrid cultivar Taxodium hybrid ‘Zhongshanshan 406’. 【Method】 The soil culture method was adopted to simulate salt-alkaline mixed stress on T. ‘Zhongshanshan 406’, replicating the characteristic qualities of coastal soils. The following parameters were measured: plant height, ground diameter, fresh weight, dry weight, chloroplast pigment, net photosynthetic rate, stomatal conductance, intercellular CO₂ concentration, and light response curve. 【Result】All T. ‘Zhongshanshan 406’ individuals survived after 45 days of salt-alkaline mixed stress, and the plant height, ground diameter, and root shoot ratio of 3, 5 and 8 g/kg treatments exhibited no significant changes, compared with the control, but the biomass of roots and leaves in the 8 g/kg treatment was signi-ficantly lower than that of the control. Salt-alkaline mixed stress also had no significant effects on leaf photosynthetic pigments, stomatal limitations, and intercellular CO₂ concentration. However, the net photosynthetic rate, transpiration rate, and stomatal conductance decreased in salt-alkaline mixed stress. The light compensation point was maintained at a lower level due to salt-alkaline mixed stress. The light saturation point of the 5 and 8 g/kg treatment groups decreased significantly, and the photosynthetic light intensity response curve showed obvious light saturation limits under salt-alkaline mixed stress. 【Conclusion】 The T. ‘Zhongshanshan 406’ survived under a salt-alkaline mixed stress of less than 8 g/kg. The leaf net photosynthetic rate was significantly reduced by a saline-alkali mixture stress that was higher than 5 g/kg. Non stomatal factors were the main causes of the decline in photosynthetic rate. The T. ‘Zhongshanshan 406’ plants alleviate salt stress on photosynthesis by adapting light utilization and by improving instantaneous water use efficiency, which exhibited strong adaptability to salt-alkaline conditions. The T. ‘Zhongshanshan 406’ has proved to be an excellent tree species for greening saline and alkaline lands.