The NBA league is a competition founded by the National Basketball Association (NBA) in the United States, and its intensity and level of competition are recognized by the world as the world's best.

In 1896, the first basketball organization in the United States, the National Basketball League (NBL), was founded, but at that time, the rules of basketball were not perfect, and the organization was not perfect.

On April 6, 1946, Walter A. Brown, the owner of Boston Garden, initiated the establishment of the "American Basketball Association (BAA)", Brown first proposed the high salary system and contract system that later became the two cornerstones of modern professional basketball. The contract system means that a player can only sign a contract with one club, and a player reserve system is set up in case the player leaves the team suddenly.

In 1949, thanks to Brown's efforts, the two major basketball organizations in the United States, BAA and NBL, merged to form the National Basketball Association (NBA). Brown also became the founder of what would later become known as the Boston Celtics. The NBA was founded with 17 teams that played in three divisions, with the Minneapolis Lakers from the NBL relying on height 2. The help of George McCan, the No. 1 center of the United States at 09 meters, won the championship of the first season of the NBA. From the 1954-55 season onwards, the NBA was naturally eliminated by the Eastern Conference and the Western Conference. Among them, the Eastern Alliance is divided into the Atlantic Zone and the Central Zone; The Western Union is divided into the Central and Western Regions and the Pacific Region.

In 1952, in order to limit the scoring ability of the first center McCan, the NBA expanded the width of the 3-second box from the original 6 feet to 12 feet. By the '60s, the NBA had expanded the width of the box to 16 feet thanks to the emergence of another super-center, Chamberlain.

Since NBA teams often used delaying tactics to lead the score, making the game unattractive to spectators, from the 1954-1955 season, the NBA began to implement a 24-second system, that is, each team could not exceed 24 seconds per offense

In 1967, a new basketball organization, the ABA (American Basketball Association), was formed, with George McConn as its first president. ABA adopts red, white and blue basketball, and implements a long-range shooting 3 system, and also holds a slam dunk contest every year.

It was annexed by the NBA in 1976, and since then, the NBA has formed a monopoly on the American basketball industry.

Since 1979, the NBA has implemented a 3-point shooting system. In order to avoid the disparity in the strength of each team, the NBA has established an annual "rookie selection system", which ranks the college players who graduated that year according to their level, and then each club selects them in turn according to the final ranking of the league that year.

Wealthy teams are exempted from monopolizing star players with high salaries, and the NBA imposes a total salary limit for each team. If you spend a lot of money to buy stars, you can't afford to buy other good players. This system ensures that the best stars are evenly distributed among the teams, so that the strength of the teams is close.

If "high salary" and "contract" are the two cornerstones of the NBA, then the "rookie selection system" and the "salary cap system" ensure that the NBA game is intense and exciting, and the unpredictability of the game attracts many American fans to the basketball court.

The NBA league also implements a transfer system, and the transfer of NBA players cannot be bought and sold, but can only be replaced by people. From the start of the season until 9 p.m. on the 16th Thursday, teams are free to exchange players. After that, until the end of the regular season, all team personnel were "frozen". NBA transfers are exchanged with contracts and contracts.