No you can't. Outside of Germany, it can only be used on a few trains, as listed on the web page. Salzburg to Innsbruck isn't in the list.

@Somyos Kiataramkul That’s possible if you don’t use the direct trains from Salzburg to Innsbruck. You need to take any train to Rosenheim and change there for a direct DB-ÖBB cooperation train to Italy (coming from München) where the German Rail pass is valid even for Innsbruck.