NOVELTY - Marine by-product fermentation concentrated fertilizer composition measured by high-efficiency liquid chromatography comprises /(10% of amino acids and /(2% of copper, iron, manganese, boron and molybdenum. The composition has a pH of 5-6 which indicates the product is faintly acidic and a density of 1.1-1.35 g/ml, which is higher than the density of water, is in between a liquid form, and is soluble in water.    USE - Used as a marine by-product fermentation concentrated fertilizer composition.    ADVANTAGE - The fertilizer composition is produced by fermenting marine by-products with microorganisms and fermented in a fermentation container closely with effective microorganisms that can decompose organic matters, thus reducing the pollution to environment, the waste of resources and carrying out recycling of resources.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) producing the marine by-product fermentation concentrated fertilizer composition, comprising: sorting raw materials and introducing the raw materials into different containers such that the volume of the raw materials in each container accounts for 60% of the volume of the container, pouring an effective microorganism mixed liquor (20% of the volume of the containers) into each container, adding seawater (15% of the volume of the containers) into each container, adding molasses (5% of the volume of the containers) into each container, and placing the containers in a natural condition closely to ferment the raw materials for the first time for 90 days, extracting first-time fermented liquors and mixing the liquors equivalently, adding an effective microorganism mixed liquor (10% of the volume of the containers into each container, adding molasses accounting for 5% of the volume of the containers) into each container, preparing a mixture of micro-elements (5% of the volume of the containers) as required by plants, performing fermentation for the second time for 2-3 weeks to obtain an amino acid mixed liquid or a mixed amino acid liquid containing micro-elements, and extracting the liquid to package; and    (2) a method for using the marine by-product fermentation concentrated fertilizer composition by performing foliage dressing and root feeding on crops.