The bearded winger will make his sixth start since making his debut last month in the same competition against rivals Espanyol.
Turan has also started in every cup game he has been eligible for – he missed the last Spanish Cup game against Athletic Bilbao due to having the flu.
Barcelona boss Luis Enrique will start with Luis Suarez, Lionel Messi and Neymar upfront meaning Turan will start on the right side of midfield.
Messi and Andres Iniesta will play their ninth Copa del Rey game tonight as Barcelona aim to keep their 28 game unbeaten run alive.
Barcelona v Valencia
Stadium: Camp Nou
Kick-Off: 20:00 GMT
Barcelona (4-3-3): 1. Ter Stegen 3. Piqué 5. Sergio 7. Arda 8. Iniesta 9. Suárez 10. Messi 11. Neymar 18. Alba 22. A. Vidal 24. Mathieu
Subs: 25. Masip 4. Rakitic 15. Bartra 17. Munir 20. Sergi Roberto 21. Adriano 23. Vermaelen
Manager: Luis Enrique
Valencia (4-3-3): Ryan; Barragan, Mustafi, Santos, Gaya; Gomes, Danilo, Parejo; Rodrigo, Cancelo, Siqueira
Manager: Gary Neville