The invention discloses an automatic most frequently used channel switching method for a set-top box. The method includes the following steps that 1, whenever the set-top box works, channel information and channel serial numbers of broadcasting are acquired; 2, whenever the set-top box works, the serial numbers of channels watched by a user and the accumulative watched times of each channel serial number are counted in real time; 3, whenever the set-top box works, the accumulative watched times of each channel are recorded, and the channel serial numbers are sequenced from large to small according to the values of the watched times; 4, when the set-top box is started next time, the set-top box is triggered to switch a channel to the channel serial number with the largest watched time value as soon as started, and a largest channel serial number is switched to randomly when the values are the same. According to the method, the most frequently used channel is automatically switched to when the set-top box is started, so that selection blind spots of the user are greatly reduced when the set-top box is started, and the channel selection process in startup is simplified. Therefore, the most frequently watched channel can be positioned as soon as the user starts the set-top box, and the method is better conformed to modern lazy thought.