The invention belongs to the technical field of mobile communication, in particular disclosing a high-speed railway mobile network covering method based on a distributed antenna and a fixed switching channel. BBU+RRU radio frequency remote technology is adopted to conduct high-speed railway linear covering; N numbered channels are divided into a logic channel; N numbered RRUs cover a logic channel; a BBU corresponds to a logic channel; the adjacent part of two logic channels is independently provided with an RRU which is not only connected with the BBU corresponding to the previous logic channel, but also connected with the BBU corresponding to the next logic channel; the covered range of the independent RRU is defined to be the fixed switch channel, and fixed direction switching is completed by utilizing the fixed switching channel and the train operating direction at the edge of the channel. The switching process is simple in operation and has accurate, thus greatly lowering the probability of drop-call during switchover at the edge of the channel and avoiding ping-pong switchover of the channel.