This paper discusses the new distribution network construction， planning and operation mode under the background of smart grid， and proposes new ideas on efficient planning， construction and operation for smart distribution networks. Firstly， the future distribution network will possess the fast network transfer capability of transferring the load from one substation to another through feeders with tie-lines. Then， the theory of total supply capability（TSC） is described， which takes the fast network transfer capability into account. Further， some vital issues for distribution system development in China are treated: the distribution systems power supply potential to tap is very great following large-scale construction and reinforcement via network optimization; the capacity-load ratio can be reduced to save investment in network optimization; the main economic benefit of distribution automation is from higher efficiency of power networks; it is necessary and feasible to simplify the complex inter-connected urban distribution networks; network structuring and conductors should be individualized as well as standardized; a security and efficiency-based framework consisting of monitoring， alarming， control and optimization should be implemented in operation and dispatching for smart distribution systems. Finally， a new distribution planning idea based on TSC optimization is proposed with a case study， in which the existing network is given priority to serve newly increased load while attending to the building of new substations and feeders next.