In the TV series Romance of the Three Kingdoms, Guan Yu always wears a green hat. Guan Yu wears a green hat or even a green dress, which does not have the meaning of "green hat" in modern definition. In fact, wearing green clothes has three meanings for Guan Yu, that is, green represents Guan Yu as an example from the bottom people, symbolizes his loyal temperament and also means his miserable life.

Actually, Guan Yu's hat is not green, but blue. In Guan Yu's era, cyan and green didn't mean any swearing, but only represented the clothing colors at the bottom of society. Guan Yu is a soldier of civilian origin. Before the Song Dynasty, he was even a low-level protector of Buddhism and Taoism. Now, Guan Yu's bravery is well known, which means that Guan Yu is an example to the bottom people, so Guan Yu in blue represents that he is a hero from the bottom people.

At first, the green dress was given to Guan Yu by Liu Bei. Everyone knows Guan Yu's feelings for the big fellow. From beginning to end, Guan Yu has always been a representative of loyalty, and even been called "warrior sage" by the world. So because it was a gift from Liu Bei, the son of the big fellow, Guan Yu loved it very much and regarded it as a gift from the big fellow. Even later, Cao Cao wanted to make a new dress for Guan Yu, and Guan Yu refused. So this green dress can also be regarded as Guan Yu's loyalty to the big fellow.

In life, green also has this sad meaning, therefore, this set of green clothes can also imply Guan Yu's miserable life. Guan Yu went through numerous hardships in his life and was born in humble origins. Finally, he was framed by traitors and died in battle. The images given to Guan Yu in TV series are all green robes, which can also reflect the sympathy of future generations for Guan Yu's tragic experience in his life to some extent.