A channel buffering method is for dynamically altering a number of channels for an Internet protocol television (IPTV). The method is applicable for a home gateway (HG) having a channel section used for channel buffering. After the HG has received two consecutive channel-switching requests, the HG compares whether the two requests are similarly directed to switching a channel towards the same direction or not; if yes, a cumulative switching frequency is set, and two trimming numerical values are set through the cumulative switching frequency, and thus, the channel section for buffering the channels can be dynamically adjusted through the two trimming numerical values.