Which Chinese general defeated Kanishka?

Pen Chao (also known as Ban Chao) was the Chinese general who was successful in defeating Kanishka. As per the book of the Later Han Dynasty, Hou Hanshu,  general Ban Chao fought battles near Khotan with a Kushan army of 70,000 men.

He was successful in repelling the Kushans following a scorched-earth policy in 90 AD. The territories of Kashgar, Khotan and Yarkand were important to Kanishka as their control would give him unlimited access to the Silk Road, thereby establishing a trade route between South Asia and the Roman Empire.

For further reading check the following articles:

• Prehistoric Age in India
• Kushan Empire
• Prehistoric Rock Paintings