An embodiment of the invention discloses an unauthorized carrier preamble configuring method comprising the following steps: configuring a PRACH configuration message, wherein the PRACH configuration message includes sub-frame position information, first CCA interval position information, a channel detection mechanism, preamble format information and preamble sending position information, the sub-frame position information shows a sub-frame where M to-be-sent preambles are located, the first CCA interval position information shows the position of a CCA interval before each of the M to-be-sent preambles on the sub-frame or on a sub-frame previous to the sub-frame, the channel detection mechanism shows whether user equipment detects that an unauthorized carrier is in an idle state under instruction, and the preamble format information shows that the to-be-sent preambles are format-4 preambles; and sending a control signaling carrying the PRACH configuration message to the user equipment. Other embodiments of the invention disclose a preamble receiving method and related equipment. By using the methods and the related equipment of the invention, the access delay is reduced.