Since the addiction induced by consumer’s self-control problems is prevalent in many Chinese industries，this paper introduces two features of addiction proposed by O’Donoghue and Ｒabin ( 1999a，2002) : habit-forming and negative internalities，into duopolistic price competition with vertical differentiation．: habit-forming and negative internalities，into duopolistic price competition with vertical differentiation．Firms’equilibrium pricing strategies are investigated when consumers are rational，naive and sophisticated，and the equilibrium price of each firm and the corresponding market share with each other in these three cases are also compared． It is found that when consumers are rational，price competition generates a unique equilibrium． By contrast，when consumers are quasi-hyperbolic discounters，the competition between firms may have multiple equilibria，which attributes to consumers’overconfidence in their future consumptions or sophistication． Meanwhile，under each of the three behavioral types of consumers，three factors will affect the firms’equilibrium prices and corresponding market shares: the consumer’s initial experience portfolio of the two addictive products，the parameter of habit-forming，and the size of negative internalities．