After a keenly-fought first set, the world number three breezed through the second without dropping a game.
Radwanska made light of a niggling injury that saw her right shoulder taped up.
She took particular advantage of Halep's weak serve, winning 21 of 32 points on the Romanian's first serve.
The Pole is in good form going into the French Open, where she plays Serbia's Bojana Jovanovski in the first round.
