NOVELTY - Making algae plant nutrient growth regulator, involves washing fresh seaweed using water, soaking, then crushing into algae slurry, and/or performing steam dry softening treatment of seaweed, and soaking for 3-4 hours with clean water, removing sand and salt, then crushing into algae slurry; then performing primary enzymolysis, secondary enzymolysis and tertiary enzymolysis using cellulose, papain and pectin enzymes, where the preserving temperature is 50-55 degrees C and period is 4-6 hours for each enzymolysis, then filtering, and concentrating the enzymolysis liquid, to obtain the product.    USE - For making algae plant nutrient growth regulator (claimed) used as plant growth regulator applications.    ADVANTAGE - The method is environment-friendly with low cost; improves the activity and stability of the algae; improve the yield of the crops; and produces algae plant nutrient growth regulator with low energy consumption. The algae plant nutrient growth regulator increases crop yield; improves the plant absorption nutrition ability; and improves the quality of crop. The raw materials used in method are not limited by season and region.    DETAILED DESCRIPTION - Preparation of algae plant nutrient growth regulator, involves (a) washing fresh seaweed using water, soaking, removing the sand and salt, then crushing into algae slurry, and/or performing steam dry softening treatment of seaweed for 20-30 minutes, and soaking for 3-4 hours with clean water, removing sand and salt, then crushing into algae slurry; (b) carrying out primary enzymolysis of the algae slurry by adding algae slurry into enzymolysis tank, adjusting pH to 6-7, and heating at 50-55 degrees C, adding 16-140 U/g cellulose enzyme, where the amount of cellulose enzyme is 0.8-30 mass%, stirring evenly, preserving at temperature of 50-55 degrees C, where the enzymolysis time is 4-6 hours; (c) performing secondary enzymolysis of the prepared primary enzymolysis algae slurry of step (b), adjusting pH to 6-7, and heating at 50-55 degrees C, adding 60-80 U/g papain enzyme, where the amount of the papain enzyme is 0.1-0.5 mass.%, stirring evenly, preserving at temperature of 50-55 degrees C, where the secondary enzymolysis time is 4-6 hours; (d) performing tertiary enzymolysis of the prepared secondary enzymolysis algae slurry of step (c), adjusting pH to 3.5-6, and heating at 50-55 degrees C, adding 3-6 U/ml pectin enzyme liquid and carried out tertiary enzymolysis, where the amount of pectin enzyme is 2-5 mass.%, stirring evenly, preserving at 50-55 degrees C, where the enzymolysis time is 4-6 hours, to obtain enzymolysis liquid; and (e) after enzymolysis, filtering the enzymolysis liquid using plate-and-frame press filter, adjusting pH to 7, and separating residue, decompressing obtained supernatant liquor to the density of 1-3 grams per cubic centimeter, and concentrating at 30 degrees C, to obtain the algae plant nutrient growth regulator.