A method for generating a preamble sequence and determining a cyclic shift. The method includes: when set a piece of root sequence can only generate one preamble sequence and there is no cyclic shift restriction, setting the cyclic shift step length NCS to be equal to 0 and the corresponding cyclic shift amount Cv=0, at this time the root sequence is directly used as the preamble sequence; when set a piece of root sequence can generate a plurality of preamble sequences and there is no cyclic shift restriction, the cyclic shift step length NCS being not equal to 0, at this time the cyclic shift amount Cv=v·NCS, wherein v=0, 1, 2, . . . , └NZC/NCS┘−1. This method is applied to the situation that a root sequence generates a preamble sequence, and the method for generating the preamble sequence is simple and easy to operate.