Lattice light steel frame is a new type of structural system, combining general steel framework which is composed of lattice column and lattice beam with lattice light steel keel of the partitions and floors, the system takes full advantages of both structural systems, with high speed construction, less steel consumption, good earthquake-resistance etc., and possesses good prospects. The paper describes the system construction approach and the characteristics of lattice light steel frame system, and provides a project example of a villa. The design method and calculation model of the project are presented. Calculation results meet the specifications’ requirements, proving the new system can be applied to practical engineering. The paper gives guidance for application and research of this new system.