Disclosed is a nonstop traffic system using a half (½) cloverleaf and a traffic method applied with the same, including a loop-type traffic system for connecting a half (½) cloverleaf (100) to half (½) underground U-turn lanes (200E, 200W, 200S and 200N) that can make vehicles drive and pedestrians walk nonstop in every direction without relation to traffic signals at existing intersections or roadways for left-turn and U-turn, and crosswalks. The half (½) cloverleaf (100) is constructed at existing intersections and the half underground U-turn lanes (200E, 200S, 200S and 200N) are constructed on left-turn roadways in existing four directions (East, West, South and North) that connect to the intersections, U-turn roadways and crosswalks. As mentioned, all structures in the nonstop traffic system using the half (½) cloverleaf in a loop-type that connects the half (½) cloverleaf (100) to the half (½) underground U-turn lanes (200E, 200W, 200S and 200N) in four directions (East, West, South, North) is adopted to the bisectional construction method, thus the height of all lanes can be differentiated. As mentioned, the half (½) cloverleaf (100) includes a half (½) overpass (10), a half (½) underpass (20), a half (½) underground U-turn roadway (30) and a half (½) ground pedestrian bridge (40). Moreover, the half (½) underground U-turn lanes (200E, 200W, 200S and 200N) includes a half (½) overpass (50), a half (½) underground U-turn roadways (60) and half (½).