Box theory refers to the formation of a certain price region in the process of price operation. That is, the price fluctuates within a certain range, thus forming a box with price operation. When the price falls to the bottom of the box, it will be supported by buying, and when the price rises to the top of the box, it will be under the pressure of selling. Once the stock price effectively breaks through the top or bottom of the original box, the price will move into the new box, and the top or bottom of the original box will become an important support and pressure level.