Abstract: Due to α radioactive decay plutonium is vulnerable to aging. The behavior of helium in plutonium is the foundation for understanding plutonium self-radiation damage aging. Molecular dynamics (MD) technique was performed to investigate the behavior of defects, the interaction between helium and defects, the processes of initial nucleation and growth of helium bubble, and the dependence of helium bubble on the macroscopical properties of plutonium. Modified embedded atom method (MEAM), Morse pair potential and the Lennard-Jones pair potential were used for describing the interactions of Pu-Pu, Pu-He and He-He, respectively. The main calculated results show that helium atoms can combine with vacancies to form helium-vacancy cluster (i.e. the precursor of helium bubble) during the process of self-radiation as a result of high binding energy of an interstitial helium atom to vacancy; helium bubble’s growth can be dominated by the mechanism of punching out of dislocation loop; the pressures of helium bubble in plutonium are at the level of GPa and the swelling induced by helium bubble is very small.