The invention provides effective technology for extracting active ingredients of Entermorpha and a method for preparing an Entermorpha alga 
fertilizer. The method is characterized by comprising: taking the Entermorpha as a 
raw material, effectively extracting the active ingredients of the Entermorpha through technical processes such as pretreatment of raw materials, leaching, 
neutralization, concentration and combination, taking an extracting solution as a base fluid, combining the extracting solution with at least one composition of 
humic acid, 
urea, 
potassium dihydrogen 
phosphate, potassiumsulfate, monoammonium 
phosphate and microelement, and preparing the high-activity Entermorpha alga 
fertilizer. The Entermorpha alga 
fertilizer is rich in active substances of 
algae, not only can strengthen 
photosynthesis of crops, increase the yield of the crops and improve the product quality but also can strengthen the 
cold resistance, the 
drought resistance, the 
stress resistance and the 
disease resistance of the crops, promote earliness of the crops and increase the fertile flower percentage and the fertile fruit percentage, has lower production cost, good 
solubility and safe use, is friendly and harmless to human beings, domestic animals and the 
natural environment, and is a novel environment-friendly fertilizer suitable for modern 
agriculture.