Abstract: The pea protein isolate ( PPI) was isolated from the waste water of bean vermicelli factory. Through the study of extraction process, the extraction condition was finally set.The condition was extract at pH12.0, solid-liquid ratio 1 ∶ 20 ( g /mL) , 30℃ for 30min. In this method, the extraction rate finally reached 62.25%. Total amino acids analysis indicated that the amino acids had not been destroyed through processing, the result showed that PPI had a high nutritional value. Physicochemical and functionality of PPI and soy protein isolate ( SPI) were compared and analyzed.Except oil and water absorption capability, the functionality of PPI was similar to SPI, such as foaming and emusifying capability. So PPI can be used as a subsititute for SPI. Through the differential scanning calorimetry ( DSC) , two endothermic peak were found, one of them was at 87.67℃ for vicilin and the other was at 104.28℃ for legumin.This may be due to the change of protein structure in the isolate procedure.