In order to verify the practicability of interspecies cross between Pyropia haitanensis and other Pyropia, cross experiment between P. haitanensis from the temperate water of China and P. radi from the tropical water of India was carried out in the laboratory, marked with the color and size of the vacuoles and the chloroplasts in cells of parental blades. P. haitanensis was used as female parent, and its blades show brown green with an obvious pigment in cells of blades. P. radi was used as male parent, and its blades show brown in color and the cells of blades containing a large vacuole and small chloroplasts. Among the F₁ gametophytic blades from the cross of P. haitanensis (♀) × P. radi (♂), two parental colors (Ph and Pr) and four new colors (Ph′, the size of the vacuole similar to Ph and the color of the chloroplasts slightly yellower than Ph; Pr′, the size of the vacuole smaller than Pr and the color of the chloroplasts redder than Pr; Pr″, the size of the vacuole between Pr and Pr′ and the color of the chloroplasts lighter than Pr′; Pr, the size of the vacuole similar to Pr and the color of the chloroplasts slightly yellower than Pr) appeared. Linear segregation of colors occurred in the F₁ blades, and therefore, the color sectored blades with 2-4 sectors were formed. There were a large number of color sectored blades and a few of single color blades. These results indicate that the interspecies cross between P. haitanensis and P. radi succeeded and the F₁ gametophytic blades could survive and be fertile，which laid the foundation for the further selection of the new strains.