We compared the methods of crude phycoerythrin extraction from Porphyra yezoensis, a main economic red alga in China.Porphyra yezoensis thallus was broken with “swelling & smash” method, and crude extract was dealed in sequence with chemical reagent such as activated carbon, rivanol or physical condition such as isoelectric point, concentration, pH, temperature and differential centrifugation. It showed that the purity of phycoerythrin increased when activated carbon was heavily applied alone. When usage of activated carbon achieved two percent of that of Porphyra yezoensis, the effect was best. And this method was much better than combined using of activated carbon and rivanol on a small scale. On the other hand, ammonium sulfate precipitation combined with pH regulating increased the purity, which was in line with concentration of solution and arrived at topmost purity of 1.35, which achieved 1.42 after differential centrifugation followed. While isoelectric precipitation or temperature control decreased the purity. This research laid the groundwork for preparation of phycoerythrin from Porphyra yezoensis