It is affirmed that China's bronze smelting technology in Qin Dynasty reached a very high level, and the sharpness and combat capability of weapons were superior to those of early ironware. The crossbow ensures the ability of long-range strike. There were many troops in the Qin dynasty, and large-scale wars involving hundreds of thousands of troops often occurred during the Warring States period, which was rare in Europe. I think someone in front said that the Qin Dynasty had little experience in war and only fought six countries and Xiongnu. Rome went through wars with many civilizations. I suggest that the student go back and study history books. During the period of Qin's development, he struggled with the surrounding ethnic minorities, such as Zurong, Shenshu, Fuyu, Donghu, Xiongnu, Yueshi, Qiang, Wusun, Loulan, especially Zurong, Donghu, Xiongnu and the vassal states that were enfeoffed in Zhou Dynasty. China's art of war in the cold weapon era can't be compared with the ancient Romans. At that time, there were many military masterpieces, such as Liu Tao, Sanlve, Sima Fa, Sun Bin's The Art of War, Woods, Liao Weizi and Sun Tzu's Art of War. A Hannibal went into Rome alone, and the Roman army was not enough to fill the hole. If 100 men fight 100 men, the Roman army may win more. If 10,000 people fight against 10,000 people, Qin Jun will win. The bigger the battle, the more confused the Romans were.