The earliest catapult in China appeared in 5th century BC, that time around the Warring States Period. In the Records of the Three Kingdoms (三國志), it also has the description of the catapult. In Chinese technology, the trebuchet is the oldest type of catapult. From the Qin and Han onwards, catapult became a common characteristic of Chinese siege warfare.
The earliest battle record the use of catapult is Battle of Guandu (官渡之戰). It was in 200 CE, Cao Cao(曹操) won this battle rely on the catapult. His adversaries have numerically superior forces. The destructive force of the catapult made them win this battle.
Catapult became a key reason in the success of the expedition of 668 BC China against Korea. From Northern and Southern dynasties to Tang dynasty, catapults keep using in the siege and the scale becomes bigger.
In the Northern Song Dynasty, the catapult was used very often in the battle between Jin (金國) to defend a city and siege. To sum up, in Chinese cold weapon era, the catapult took an important role in the war.