A method for dedifferentiating adipose tissue stromal cells (ATSC) is provided. When the ATSC is treated under hypoxia condition and with a 4-(3,4-Dihydroxy-phenyl)-derivative (DHP-derivative), expression of stemness genes, cellular growth-related genes and cellular mobility-related genes increase, and expression of histone and DNA methylation-related genes decrease so that cell proliferation increases and pluripotency for differentiating into adipocytes, osteocytes, myocytes, beta cells and cartilage cells is acquired. When the dedifferentiated ATSC is implanted into animal model with spinal cord injury and diabetic animal model, effects of nerve regeneration and increased blood surge level are confirmed. As a result, the method for dedifferentiating the ATSC can be effectively used in the stem cell research, tissue regeneration and development of cytotherapeutic medicines.