Abstract: Yoram Barzel built out a state model of the New Institutional Economics，using property theory.Yoram Barzel holds that the functions of the state is to ensure successful cooperation and exchange among social parties；the state′s scale depends on the scale of population and territory；the scope of the state is determined by the proportion of state contract value to the total value of domestic products；the state′s type，which may evolve between the state ruled by law and the one of dictatorship.His theory enriches the research of politics but has some logic defects as Barzel neglects the differences in the natures of individual and organization and fails to clearly define such important concepts as “power”and“collective action”.

Key words: Barzel, state, collective action, property, state ruled by law, state of dictatorship