In　this　paper,　homoclinic　bifurcations　and　chaotic　dynamics　of　a　piecewise　linear　system　subjected　to　a　periodic　excitation　and　a　viscous　damping　are　investigated　by　the　Melnikov　analysis　for　nonsmooth　systems　in　detail.　The　piecewise　linear　system　can　be　seen　as　a　simple　linear　feedback　control　system　with　dead　zone　and　saturation　constrains.　The　unperturbed　system　is　a　piecewise　linear　Hamiltonian　system,　which　contains　two　parameters　and　exhibits　quintuple　well　characteristic.　The　discontinuous　unperturbed　system,　which　is　obtained　by　reducing　the　two　parameters　to　zero,　has　saddle-like　singularity　and　homoclinic-like　orbit.　Analytical　expressions　for　the　unperturbed　homoclinic　and　heteroclinic　orbits　are　derived　by　using　Hamiltonian　function　for　the　piecewise　linear　system.　The　Melnikov　analysis　for　nonsmooth　planar　systems　is　first　described　briefly,　and　the　theorem　for　homoclinic　bifurcations　for　the　nonsmooth　planar　systems　is　also　obtained　and　then　employed　to　detect　the　homoclinic　and　heteroclinic　tangency　under　the　perturbation　of　a　viscous　damping　and　a　periodic　excitation.　Finally,　the　chaotic　attractors　and　the　bifurcation　diagrams　are　presented　to　show　the　bifurcations　and　chaotic　dynamics　of　the　piecewise　linear　system.