Abstract: Objective To investigate the correlation between the gene polymorphism of mitochondrial DNA（mtDNA） modulating region（D loop） and the performance of pilots. Methods Gene polymorphism of the mtDNA D loop was assessed in 86 pilots and 80 healthy control subjects by PCR-RFLP. Results A statistical difference was found in the distribution of gene polymorphism between pilots and control subjects. Conclusion The mtDNA D loop plays an important role in the performance of pilots.