Aim To screen for the mitochondrial DNA 4977bp (mtDNA4977) deletion in the patients with alcoholic fatty liver disease (AFLD). Methods Polymerase chain reaction (PCR) was carried out to detect mtDNA4977 deletion within 90 cases of AFLD plus 90 of normal controls. The ultrasound examination was conducted for the liver tissues of AFLD to compare liver function, blood fat level, body weight, and mtDNA4977 deletion among different ultrasound grades of AFLD. Results With the aggravation of fatty change in live tissues of AFLD, deposition of both triglyceride (TG) and body mass index (BMI) in liver increased significantly (P<;0.05). The mtDNA4977 deletion was detected in 35.56% (thirty-two cases) of the AFLD patients tested and occurred primarily ultrasound grade II or III, giving a significant difference compared to grade 0/I and normal live tissues (P <;0.05). Conclusions A small portion of the AFLD patients had the mtDNA4977 deletion, and this mutation was detected only in high-grade fatty change of AFLD.