A new strain (SR-11) was selected from an intraspecific hybridization of a new cultivar (SF-2, ♀) and an improved strain (HR-6, ♂) of Pyropia haitanensis, and the characteristics of blades thickness, growth rate, phycobiliprotein content, and differentiation rate of conchocelis of SR-11 were analyzed through laboratory culture. After being cultured for 45 days, the mean thickness of SR-11 was 22.9 μm, which was 37.1% and 18.5% thinner than that of SF-2 and HR-6, respectively; the phycobiliprotein of SR-11 was 94.6 mg/g, increased by 4.1% and decreased by 8.4% compared with that of SF-2 and HR-6, respectively. After being cultured for 55 days, the mean length of the SR-11 was 293.7 cm, which was 3.1 and 7.2 times longer than that of SF-2 and HR-6, respectively. After the conchocelis inoculated shell were raised the temperature and shrunk of light time, the time for the emergence of a lot of conchosporangial branches in SR-11 was shorter than that of SF-2. The total number of conchospores released from per shell in SR-11 was 144.5 × 104, which was 78.1% and 11.9% higher than that of SF-2 and HR-6, respectively. In summary, the SR-11 has thinner blades, and its fresh blades may be further processed into higher value-added products. Besides, it has the advantages of fast growth, high quality and large number of conchospores released, which is expected to be applied in production cultivation.