The 23-year-old player has penned a four-year contract for an undisclosed fee.
Erwin was a member of Kilmarnock last season and scored five goals in 34 matches.
He has also played for Motherwell, Arbroath, Leeds United, Bury, and Oldham Athletic.
Erwin has been capped by Scotland at under-17, under-18 and under-19 levels.
He is Tractor Sazi’s fourth foreign-based player after Englishman Harry Forrester, Irish Anthony Stokes and Japanese Yukiya Sugita.