In a nutshell, the Chinese, under the leadership of the Muslim eunuch Zheng He and commissioned by Emperor Yongle, embarked on maritime voyages covering Southeast Asia and the lands around the Indian Ocean. With over 300 ships and a crew of about 27,000 people, this fleet dwarfed that of the European voyages. On his voyage to the New World, Christopher Columbus only brought three ships along with him. Seeing that the Chinese had a fleet 100 times that of Columbus' fleet speaks volumes about the possible military power of the Chinese navy.
Interestingly, the Chinese did not decide to continue their maritime voyages, and did so rather abruptly. Scholars speculate that the reason for this was due to the death of Zheng He. With no one to lead these voyages, and since the Chinese government never cared for these voyages anyway, the Chinese fleet was left to rot and the voyages stopped.
Strayer suggests that it was maybe because the Chinese stopped their maritime voyages that allowed the success of the European voyages. Because of the Chinese presence in Southeast Asia and the Indian Ocean, much of the area was regulated by the Chinese, making the area safer. Therefore, European travelers were allowed to travel to these areas without experiencing major difficulties. However, Strayer also notes that if the Chinese never stopped their maritime voyages, then world history as we know it could have ended up quite differently. If the Chinese remained a significant presence in Southeast Asia and the Indian Ocean, then the Europeans would have a much harder time exerting their influence over the area. This, in turn, would prevent much of the European supremacy and colonialism that resulted in later centuries.