The conchospore gametophytic blades of the wild-type strain of Pyropia crispata were irradiated with different doses of ultraviolet ray. After being cultured for about 4 weeks, many color-mutated cell clusters including yellow green, ruby red, yellow orange and so on,appeared on the irradiated blade. The statistical analysis showed most of the color-mutated cell types are yellow and the dose of 80 μW/cm² attained the best mutagenic effect. Single mutated cell was isolated enzymatically from the color-mutated blades and was regenerated into blades, in which some single-color mutants were selected:PC-JH (orange brown), PC-ZH (ruby red), PC-HL (yellow green) and PC-QL (light green). Their homozygous strain were gotten by parthenogenesis, respectively. The color and morphology of the F₁ gametophytic blades of each mutant strain showed uniform color and were same with its mother blade. The results indicated mutant characters such as color can be stably inherited in each mutant strain. Each mutant strain featured their own characteristics in in vivo absorption spectra of the blade, contents of chlorophyll a(Chl.a), phycocyanin(PC), phycoerythrin(PE) and their ratio, different from wild-type strain's. Compared with the wild-type strain (PC-WT), the content of PC and the value of PC/Chl.a of the two green-type strains(PC-HL, PC-QL) increased significantly, while the value of PE/PC decreased significantly and was close to one. The content of three pigment proteins in the orange-yellow mutant (PC-JH) was reduced, and the PC/Chl.a value was also lower, but the PE/Chl.a and PE/PC values were higher. The PE content of the date-red mutant (PC-ZH) increased significantly. Correspondingly, the values of PE/Chl.a and PE/PC also increased significantly. These results indicated that UV had a good mutagenic effect on Pyropia crispata blade, and the obtained four mutant strains were stable in color. They will become important materials for genetic breeding in Pyropia crispata.