In view of good geological condition non-cliff side slope road widening or new road construction, after contrasting and analyzing the characteristics of widening pattern of roads that have been built, lattice slope foundation cantilever structure complex road is proposed. Using slope foundation column which is casted depending on hillside, its top connect with deck of bridge supporting on the cantilever beam ,thus forms the flank roadway structure. This complex road can avoid deep-digging and high filling, lower construction cost.The construction method is simple, slope is also stable. Moreover, in the course of road widening, vehicle traffic will basically not be affected. In this paper, the method of construction technology, working principles, engineering application and economic, technical efficiency and environmental effectiveness have been analyzed, it shows that in road widening under appropriate condition, this method is safe and reliable, can significantly simplify the process, lower cost, and also maximize the protection of natural ecological environment.