The phenomenon of droplet impact on a smooth, flat, partially wetted surface is studied by phase field simulation. A map of the different impact regimes is constructed for Reynolds numbers ranging from Re = 9 to Re = 9 x 10(4), and Ohnesorge numbers ranging from Oh = 3.3 x 10(-4) to Oh = 1.05. The results are compared with previous experiments from several aspects such as gas bubble entrapment, spreading radius and liquid sheet splashing, etc. The simulation proposes event predictions that are consistent with previous experiments. Our results and discussions give an overview of important characteristics during droplet impact, and provide insights on the droplet spreading after impact.