To establish a cultivation method of Petalonia fascia, seeds and seedlings cultures and growth tests were performed at the Daeri aquafarm in Haeui, Shinan, Jeollanamdo, Korea. Gametes were easily released from the mature plurilocular sporangia. They developed to crustose discoidal stolons and grew to filamentous and discoidal stolons. The indoor seeding was performed by using the 100-150 ${mu}m$long fragments of stolons on Porphyra nets and the erect thalli developed from the cuttings when the seawater temperatures were 10-15$^{circ}C$. In the experimental cultivation in the sea, 1-2mm long plantlets were found after 15 days of cultivation; after two months thalli grew to their maximal size of 215-355 mm long blades; after three months the length of thalli began to decrease due to distal disintegration and the plant color changed to yellow and epiphytic diatoms were attached on the thalli, which deteriorated the quality of products. The cultivation of P. fascia by the regeneration of filamentous-discoidal complexes was carried out successfully for the first time in Korea.