Due to the characteristics of large football field, large number of people, fierce competition and "offside" regulations, the referee must ask the athletes of both sides to wear different colors in order to accurately judge what happened on the field. At the same time, the football match stipulates that the goalkeeper can touch the ball with his hand in his own restricted area, and when there is no ball in his own goal area, he is protected to some extent. The area near the restricted area is often the most competitive and prone to problems. If the goalkeeper's clothing color is the same as other players on the field, it will be difficult for the referee to accurately and timely judge whether to handball and who should be protected. Therefore, it is required that the color of the goalkeeper's clothing must be obviously different from other players on both sides and from the referee on the court.

In the football match, in addition to the requirements of clothing color, it is also stipulated that the back of football players' jerseys and the front of shorts must have the same number. Due to the above characteristics in the football match, in order to facilitate the referee to see the movements of each player, it is required to make the numbers on the back of each player's coat bigger. Generally, the number is 25cm high,12cm wide and the stroke is 3cm wide. In this way, the number of jerseys of basketball and volleyball players is much wider (the number of basketball clothes is 20 cm higher, volleyball 15 cm, and the width of strokes is 2 cm). There are also size rules for the size of the number in front of shorts. This is not only convenient for the referee to correctly and timely see who fouls and who plays football, but also convenient for the audience in the stands far away from the stadium to see clearly the activities of each player.

First, the football uniform regulations:

1. Players are not allowed to use or wear equipment or anything (including all kinds of jewelry) that may endanger themselves and other players.

2. The basic equipment that players must have is:

① sports coat; 2 shorts (if you wear tight underwear, you must be the same color as the main color of shorts); 3 socks; ④ Leg protection;

⑤ Leggings must be completely covered by socks; ⑥ Made of suitable materials (rubber, plastic or other similar materials); ⑦ Provide appropriate protection; 8 football shoes.

3. Each goalkeeper's clothing color must be different from other players, referees and assistant referees.