The energy changes and microscopic parameters resulting from the interaction of hydrogen and two kinds of defects on carbon nanotubes chair(5

5)

chair(6

6) and zigzag(10

0) were calculated by using molecular dynamics and quantum chemistry. The average energy per atom of carbon nanotubes reflected the tension and torsion of the conjugated surface. According to the cohesive energy obtained by calculation

the interaction was found to be relevant to the type and position of the defects.Hydrogen molecule passed most easily from the defect formed by removing one carbon atom and located in the middle of carbon nanotubes. According to bond energy

bond order and net charge

it was concluded that the carbon atoms on the edge of defects were positively or negatively charged by turns

the symmetry of the defects were reduced due to the interaction of hydrogen.More negative charges were enriched on the edge

and the distribution of net charge became more inequal. The interaction of hydrogen and the defect mainly occurred on the three carbon atoms most close to the hydrogen molecule

and influenced the microscopic properties.