In　this　paper,　we　extend　the　well-known　Melnikov　method　for　smooth　systems　to　a　class　of　periodic　perturbed　planar　hybrid　piecewise-smooth　systems.　In　this　class,　the　switching　manifold　is　a　straight　line　which　divides　the　plane　into　two　zones,　and　the　dynamics　in　each　zone　is　governed　by　a　smooth　system.　When　a　trajectory　reaches　the　separation　line,　then　a　reset　map　is　applied　instantaneously　before　entering　the　trajectory　in　the　other　zone.　We　assume　that　the　unperturbed　system　is　a　piecewise　Hamiltonian　system　which　possesses　a　piecewise-smooth　homoclinic　solution　transversally　crossing　the　switching　manifold.　Then,　we　study　the　persistence　of　the　homoclinic　orbit　under　a　nonautonomous　periodic　perturbation　and　the　reset　map.　To　achieve　this　objective,　we　obtain　the　Melnikov　function　to　measure　the　distance　of　the　perturbed　stable　and　unstable　manifolds　and　present　the　theorem　for　homoclinic　bifurcations　for　the　class　of　planar　hybrid　piecewise-smooth　systems.　Furthermore,　we　employ　the　obtained　Melnikov　function　to　detect　the　chaotic　boundaries　for　a　concrete　planar　hybrid　piecewise-smooth　system.