The protoplasts were isolated enzymatically from the gametophytic blades of the wild type and red mutant of Porphyra haitanensis and from the wild type blades of Porphyra yezoensis, respectively. Protoplast fusions were made by treatment with polyethylene glycol (PEG) solution. Many heterokaryocytes formed after the PEG solution was diluted out. The rate of intrageneric fusion was 9.7%-12.4% for P.haitanensis, and 10%-11.5% for P.yezoensis. The fusion rate became higher as the molecular weight of PEG increased from 1 540 to 6 000. Fusion products that involved one red and one wild type protoplasts in P.haitanensis were picked out and individually cultured. After 30 days of culture, one of them developed into a chimeral blade composed of two sectors showing red and wild type color. While, a fusion product involving two red protoplasts developed into a red blade that has two rhizoids at the top and basal ends of the blade. However, protoplasts isolated from the blade, regenerated into red blades, which only have one rhizoid at the basal end of the blade. After culture of 15-20 days, intrageneric fusion products of P.yezoensis developed into cell masses, which released many spores to germinate into normal wild type blades.