China's rugged mountain ranges, like Tian Tze and the Himilayas worked as a barrier to the outside world. The Gobi Dessert was another natural barrier, as well as Siberia, a still frozen tundra. Because of this, it was very hard for Merchants to trade. They had to either cross the tundra, dessert, or mountain, or they had to sail around all of China by boat. When China developed the Silk Road, trading was much easier.
