Disclosed are a method and device for determining a preamble sequence of a physical random access channel. The method includes in a previous stage, receiving respective preamble sub-sequences, and determining instances of time at which the respective preamble sub-sequences are detected in a detection window; in a current stage, receiving respective preamble sub-sequences, and determining instances of time at which the respective preamble sub-sequences are detected in the detection window; and determining preamble sub-sequences belonging to a same preamble sequence according to the instances of time at which the respective preamble sub-sequences are detected in the current stage, and the instances of time at which the respective preamble sub-sequences are detected in the previous stage.