Abstract: Protein disulfide isomerase (PDI), also named PDIA1, is an archetype member of protein disulfide isomerase family, which mainly exists in endoplasmic reticulum and plays an important role in pathophysiological progress via enzyme activity and molecular chaperone function helping protein folding correctly. Amyotrophic lateral sclerosis (ALS) is a kind of neurodegenerative diseases characterized by abnormal protein aggregation. Recently, PDI mutants have been found in ALS patients and the important role of PDI protein in the development of ALS has also been confirmed. Here, we focus on the recent studies of PDI in ALS hoping to provide a novel target for the treatment of ALS.