The article discusses the features of urban and rural settlement systems, shows the difference in their types of complexity, levels of stratification and opportunities for spatial development. Being not fully taken into account, these features do not allow specialists to create adequate models of the rural settlement system and hinder decisions to strengthen the sustainability of the country side. The article reveals typical shortcomings and perspective research areas of the rural settlement system, shows its qualitative differences from the urban settlement system. All this points can further help in practical actions to strengthen the sustainability of rural settlement in Russia.