Taking Enteromorpha prolifera from Zhejiang coast as raw material, continuous extraction and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) were used to analyze the content of aluminum in Enteromorpha prolifera from different sea areas. The distribution and speciation of aluminum in Enteromorpha prolifera were investigated, and the extraction conditions were optimized. The optimum extraction parameters were as follows: crushing Enteromorpha prolifera to 20-30 meshes, HCl and NaOH concentration was 1 mol.L_^-1, and the extraction temperature was 60℃. The results showed that the total aluminium content in Enteromorpha prolifera ranged from 1585.25 mg.kg_^-1 to 1776.48 mg.kg_^-1, mainly in the form of stable aluminium and active aluminium. The stable aluminum is mainly soluble polysaccharide-bound aluminum (Al_osu), small molecule protein aluminum (Al_pros), alginate-bound aluminum (Al_swg), macromolecule protein aluminum (Alpro), and fibrous aluminum (Al_ofi), accounting for 1.77%~2.70%, 12.65%~17.11%, 39.76%~42.08%, 20.31%~22.23%, 11.99%~14.51% of the total aluminum, respectively; the active aluminum is mainly hydroxyl aluminum(Al(OH) _²⁺, Al_³⁺), AlF and Al_ofi. Soluble organic aluminium (Al_osm) accounts for 8.57% to 11.38% of total aluminium. These results may provide scientific basis for the edible safety of Enteromorpha prolifera and the standard formulation of aluminum.