A method for forming a fin field effect transistor device structure includes forming a fin structure over a substrate. The method also includes forming a gate structure across the fin structure. The method also includes forming a source/drain recess adjacent to the gate structure. The method also includes wet cleaning the source/drain recess in a first wet cleaning process. The method also includes treating the source/drain recess with a plasma process. The method also includes wet cleaning the source/drain recess in a second wet cleaning process after treating the source/drain recess via the plasma process. The method also includes growing a source/drain epitaxial structure in the source/drain recess.