Hizikia fusiformis hydroysates by five carbohydrases (Viscozyme, Celluclast, Termamyl and Ultraflo) and five proteases (Protamex, Kojizyme, Neutrase, Flavourzyme and Alcalase) were investigated for their extraction efficacy (yield and total total polyphenolic content) and antioxidative activity (DPPH radical and hydrogen peroxide scavenging activity). Termamyl and Ultraflo of the carbohydrases and Flavourzyme and Alcalase of proteases were selected by their high eficacy of extraction and antioxidative activity. Selected enzymes were used to investigate the optimum enzymatic reaction time and dosage (enzyme/substrate ratio) suitable for hydorolysis. Optimum reaction time for the enzymatic hydrolysis was 3 days and optimum dosage of hydrolysis was observed as 5%. Simultaneously, Ultraflo of the two carbohydrases and Alcalse of the two proteases were selected as the most effective enzymes. Combination of Ultraflo and Alcalase under optimum hydrolysis conditions could intensify the extraction efficacy of antioxidative materials form H. fusiformis. The hydrolysate obtained by combining the enzymes was separated into four different molecular weight fractions (<1kD, 1-10 kD, 10-30 kD and >30 kD) and recorded the polyphenolic content distribution and respective antioxidative ability. The fraction <1kD was identified as less effective and those fractions > 1kD indicated comparatively higher antioxidative activities related to their polyphenolic content.