At the earliest time, which was the Spring, Autumn and Warring States period, the concept of catapult was briefly explained in the book ‘Mozi’. Catapult was constructed on wooden artillery with thirteen feets height from the ground level. Moreover, the stands would be buried under the ground for stability. The axis was combined with wheels, axles and a rope for soldiers to pull and tow the catapult. Stones and fireballs were usually being used as projectiles.