Abstract: Technology for pulse ultrasonic-assistant extraction of phycoerythrin from Porphyra yazoensis was investigated. The optimized technology parameters, obtained by combining single-factor experiments with orthogonal experiment, are that on-time of pulse is 2 s, off-time is 3 s, ultrasonic power is 800 W, total extraction time is 60 min, extraction temperature is 20℃, the ratio of material to water is 30 mg/mL and the rotation rate of pump for mixing and cycling extractive liquid is 5 r/s. Under the optimizing technology parameters, the yield of phycoerythrin is 3.249% and its purity(OD₅₆₁/OD₂₈₀) is 0.365. Comparing with traditional extraction method, pulse ultrasonic-assistant extraction shortens extraction time from 3～20 h to 1 h.