Abstract: In June 2021, embryonal axis were selected from Kandelia obovate forest in Sanmen, Zhejiang province. Experiments were conducted on container seedling cultivation by randomized blocks design with 2 factors and 2 levels, including two container types （C1: plastic bag, C2: non-woven fabric bag） and four substrates （M1: sea mud; M2: V_peat∶V_vermiculite∶V_perlite = 4∶4∶2; M3: V_peat∶V_vermiculite∶V_perlite = 5∶3∶2, and M4: V_peat∶V_vermiculite∶V_perlite = 6∶2∶2）. In October 2021, determinations were conducted on net photosynthesis rate, relative chlorophyll content, height, ground diameter, biomass etc. of tested container seedlings. The results showed that container type significantly affected seedling height, root biomass, stem biomass, total biomass, root volume, root tip number. Height, root biomass, stem biomass, total biomass, root volume and root tip number of seedlings in container C2 increased by 8.33%, 9.47%, 15.21%, 9.72%, 33.97% and 23.55% than than in container C1. Substrate composition significantly affected seedling height, ground diameter, biomass, Dickson’s quality index （DQI）, average root diameter, net photosynthetic rate and leaf nitrogen content. Height, ground diameter, above-ground biomass, below-ground biomass, total biomass, DQI, mean root diameter, net photosynthetic rate, and leaf nitrogen content of seedlings on M2, M3, and M4 increased by 9.78 %, 13.60%, 29.25%, 20.39%, 30.06%, 30.88%, 8.75%, 24.22% and 74.44% compared with that on M1. Interaction between the two factors significantly affected seedling height, leaf biomass and root surface area.