Abstract: In this paper, the factors affecting the growth of Dendrobium officinale tissue culture seedlings were studied in order to optimize the rapid propagation system of Dendrobium officinale tissue culture. The results showed that low salt medium 1/2 MS was more suitable for the growth of Dendrobium tissue culture seedlings; the effect of adding 0.2 mg/L NAA on the growth of Dendrobium officinale tissue culture seedlings was significantly higher than other auxin; when sucrose concentration was 25 g/L and inorganic salt concentration was 1/2 MS, the osmotic pressure environment of culture medium was more suitable for the growth of Dendrobium officinale tissue culture seedlings; organic additives LH（hydrolyzed milk protein）and CH（hydrolyzed casein）could promote the growth of Dendrobium officinale tissue culture seedlings, among which 0.1 g/L hydrolyzed milk protein was the most suitable for the growth of Dendrobium officinale tissue culture seedlings, where 0.8 cm tissue culture seedlings, after 60 days of culture, reached the average plant height 2.26 cm, stem diameter 2.73 mm, rooting number 2.45, tillering amount 3.51, and the plant grew vigorously with the leaves large and dark green. This study lays a foundation for the establishment of efficient tissue culture and rapid propagation of Dendrobium officinale.

Key words: Dendrobium officinale, tissue culture seedlings, growth, influence factor