The writing brush was invented by Meng Tian, a general of the Qin Dynasty. According to historical records, after Qin Shihuang unified China, he ordered Meng Tian to lead 300,000 troops to attack the nomadic Huns there. Meng Tian led the troops to the north, recovered the Hetao, and built the Great Wall of Wan Li at the junction. Due to the rapidly changing military situation, Meng Tian needs to send a large number of letters to the mainland. At that time, people used knives to carve characters on bamboo slips. In order to carve a large number of letters, Meng Tian's hands were soaked with blood and his eyes were boiled into white rabbits. So Meng Tian tried to find a good way to write. One day, Meng Tian saw his men gesticulating with red tassels, and suddenly thought, why not tie your hair on a bamboo pole and dip some color in it and write it on white silk? He gave it a try and it worked well. So he ordered his men to make many "Mao" pens according to the law. It is located outside the Great Wall, where there are wild wolves and some people tend sheep. Wolf hair and wool have become the most convenient materials for writing pens, which are the earliest wolf pens and sheep pens. But some people think that the actual invention time is much earlier. 1954, a complete tomb of the Warring States period was excavated in Changsha, China, which contained a brush. Wrapped in a small bamboo tube, it is 18.5cm long, 0.4cm in diameter and 2.5cm in hair length, and made of fine rabbit hair. But the practice is different from the current brush. Instead of inserting the bristles into the pen holder, turn the bristles to the outer end of the pen holder, and then wrap them with thin lines and draw them on the outside. Together with the pen, there are bamboo pieces used as "paper", copper pieces for scraping bamboo pieces and small bamboo tubes for filling ink. This is the earliest and most complete brush ever discovered. Some scholars believe that the appearance of writing brush may be much earlier than the Warring States period. Because judging from the Oracle Bone Inscriptions films left over from history, the characters on tortoise shells and animal bones are unified, and some words are as thin as scratches. Some of these words are written without lettering, so people 3000 years ago may have had writing tools similar to brush. Five or six thousand years ago, some painted pottery found in the Yellow River basin also had various patterns, most of which had smooth lines. They should be painted with a brush-like tool and then fired in a kiln to achieve that effect. Meng Tian's invention of writing brush is recorded in the history books, but it seems that writing brush has been used before, but it needs exact archaeological findings to confirm it.