Embodiments of the invention disclose a method and a device for acquiring a pseudo random sequence. The method comprises the following steps of respectively dividing a first sequence and a second sequence into N segments to acquire N segments of sub-sequences of the first sequence and N segments of sub-sequences of the second sequence, computing a sequence value of each of the N segments of sub-sequences of the first sequence and a sequence value of each of the N segments of sub-sequences of the second sequence, and acquiring the pseudo random sequence according to the sequence value of each segment of sub-sequence in the first sequence and the sequence value of each segment of sub-sequence in the second sequence. The invention further discloses a device for acquiring the pseudo-random sequence. The pseudo random sequence can be quickly computed, the calculation amount can be effectively reduced, and the storage space can be saved.