Fauns and Satrys differ in a few ways, but they are much the same. Satyrs are the Roman counterparts to the greek Fauns. In some cases the mythology divides and contradict.
fauns are forest spirits. Romans connected their satyr with the Greek faun, the wild and orgiastic drunken followers of Dionysus.

However, Fauns and satyrs were originally quite different creatures. Both have horns and both resemble goats below the waist, humans above; but this is where it divides. originally satyrs had human feet, fauns goatlike hooves.