A single degree-of-freedom plastic impacting oscillator was considered under the conditions of grazing and codimension-1 bifurcations. Based on the two-and one-dimensional parameters bifurcation analysis、 the bifurcation characteristics of single-impact periodie motions was studied. The non-smooth bifurcations such as Crossing-sliding. Switching-sliding anc codimension-2 sliding bifurcations as well as the discontinuous bifureations such as grazing bifureation and uous boundary crisis were revealed. The non-sticking periodic motion and sticking periodic motion transit into each other via a crossing-sliding bifurcation. In the two-dimensional parameter region of the low frequency and small clearance

the periodic motions (1

1

1) and (1

2

1) are distributed alternately. The boundary between the two types of periodic motions is a switching-sliding bifurcation curve. The boundary crisis of chaos occurs leading the chaotic attractor and its basin to vanish.