Abstract: To study the effects of Tα1(thymosin α1) Spirulina in adding to juvenile abalone feeds,a comparison experiment was conducted in 8 pools of 23.2 m2 for each with water temperature 12.5～17.7 ℃ and salinity 30.Initial shell length and density of the juvenile abalone were 3.68±0.04 mm and 5 755±429 unit· m-2 for treatment group,3.66±0.07 mm and 5 733±169 unit·m-2 for control group,respectively.By the end of experiment,the shell length,survival rate,daily gain in length reached in 15.65 ± 0.19 mm and 15.08 ± 0.63 mm,93.57 ± 0.68% and 89.25 ± 2.48%,90.04 ± 1.49 μm·d-1 and 85.81±4.48 μm·d-1 for experiment and control groups,respectively.Results showed that adding Tα1 Spirulina in juvenile abalone cultivation increased survival rate(P0.05) significantly and stimulated abalone growth(P 0.05).The color of shell and uniformity of size were better in treated group than in control.With enzyme-linked immunosorbent assay(ELISA),it was found that adding Tα1 Spirulina in feeds enhanced the content of Tα1 in juvenile abalone(P0.05).