For overcoming some problems of present purification technology of phycoerythrin, such as too complicated process and too low yield, the method of "salting-out → ultrafiltration → hydroxyapatite column chromatography or DEAE-52 column chromatography" was used, an efficient and simple method on the purification of phycoerythrin from Porphyra yazoensis was established. Results show that: 1) when the method of ammonium sulfate salting-out is applied to purify phycoerythrin from porphyra yazoensis crude extracts with an absorbance ratio(OD₅₆₁/OD₂₈₀) of 0.365, a product with OD₅₆₁/OD₂₈₀ of 0.45 and recovery yield of 67.33% is obtained. 2) ultrafiltration with WM 50 000 Da is used for desalting and going out small molecule hetero-protein from salting-out-yield of phycoerythrin, making purity(OD₅₆₁/OD₂₈₀) of phycoerythrin reach 0.74 and recovery rate reach 93.11%. 3) hydroxyapatite column chromatography and DEAE-52 column chromatography are further used, so the maximum purities of phycoerythrin reach 2.76 and 1.74 respectively, and the recovery rates reach 59.3% and 56.81% respectively. Research results indicate that salting-out combined with ultrafiltration is a high efficient method for obtaining edible-purity phycoerythrin. And if hydroxyapatite column chromatography is used further, medicinal-purity phycoerythrin can be obtained.