What's the easiest way to get from Terracota Warriors to Muslim Market place then back to airport?

Well, you can take tourist bus line 5 (no.306), 914 or 915 back to Xian Railway Station. Take a taxi to the Muslim Market with a fare of CNY10 or so. To get back to airport, you can take a taxi to Metropark Hotel on East Street or Longhai Hotel near Railway Station to take shuttle bus.