The technological parameters for digestion process of L. trabeculata were studied with stem of wet L. trabeculata in the particle size range of 1~3 mm. The effects of Na2CO3 concentration, rotational speed, mass ratio of solid to liquid, digestion temperature and digestion time on the digestion yield and viscosity of alginate solution were examined. Based on the results of single factor experiments, the orthogonal experiments were carried out to optimize the technological parameters. The t=results showed that the optimum conditions were Na2CO3 concentration 1.67%, rotational speed 400 r/min, mass ratio of solid to liquid 1:15, digestion temperature 70℃ and digestion time 8 h. Under these conditions, the product yield of sodium alginate from L. trabeculata reached 34.80% and its viscosity was 2261.67 mPa×s, which was higher than that of commercial product (173.30 mPa×s). The relative molecular weight of prepared sodium alginate reached 11.85 kDa, and its physicochemical properties met national standard.