A simple method for the purification of porphyran from laver Porphyra yezoensis was developed to obtain information for the development of food materials with biological functionality. Crude porphyran (CP) was extracted from dried laver in boiling water for 3 h, and then fractionated using cetylpyridinium chloride into an acidic fraction (CP-F1) and a neutral fraction (CP-F2). CP-F1 was fractionated further by fractional ethanol precipitation. Fraction CP-F1-70, precipitated at an ethanol concentration of 61-70% was the major fraction containing 68.1% of the yield from the initial fraction CP-F1. The CP-F1-70 fraction displayed a single band on Sepharose CL-4B with a molecular mass of 550 kDa, indicating a homogeneous polysaccharide. The molar ratio of galactose, 3,6-anhydro-L-galactose, 6-0-methyl-D-galactose and ester sulfate of CP-F1-70 was 1:0.32:0.07:0.53. This method is very useful for rapid and large-scale preparation of purified porphyran because it is compatible with mass production.