This study aimed to investigate the optimal enzymatic hydrolysis conditions of alginic acid using Viscozyme® L, Celluclast® 1.5L, Saczyme®, Novozym®, Fungamyl® 800L, Driselase® Basidiomycetes sp., and Alginate Lyase, for production of reducing sugar. Response surface methodology (RSM) based on central composite rotatable design was used to study effects of the independent variables such as enzyme (1-9% v/w), reaction time (10-30 h), pH (3-7) and reaction temperature (30-70oC) on the production of reducing sugar from alginic acid. The coefficients of determination (R2) of Y1, Y2, Y3, Y4, Y5, Y6, and Y7 for the dependent variable regression equation were analyzed as 0.947 0.968, 0.840, 0.926, 0.923, 0.892 and 0.825. And the p-value of Y1, Y2, Y3, Y4, Y5, Y6, and Y7 within 1% (p < 0.01) was very significant. The optimal conditions were 1.0% of the quantity of the enzyme, 10.0 hours of the response time, pH 3 and 70.0oC of the reaction temperature, where the production rate was 483.1 mg/g-alginic acid, the highest of all the enzymes used.