The Silk Road used to be a business route that linked Asia, Europe and even Africa. So the complete Silk Road route spread from Chang’an (today’s Xian) in west till to the east bank of Black Sea.
Besides the cities we recommended, there are many cities in other countries along Silk Road waiting for exploring.
The Silk Road route Chinese travel companies usually talk about indicates the China part of Silk Road. Which stretches from Xian, home town of world famous Terracotta Warriors and Horses, to Kashgar in Xinjiang.