This paper proposes a transmitter filtering (TF) method for random access using physical channel identifier (PCID)-linked receiver beamforming (BF). The role of the transmitter filtering in this system is to reduce the delay spread of the multipath channel, reduce the multipath interference, and increase the received signal power gain. There is room for improvement in previous zero-forcing (ZF)-based and minimum mean squared error (MMSE)-based TF methods in terms of the trade-off between multipath interference and power gain in view of the actual channel estimation accuracy. The proposed method is characterized by the fact that the number of effective paths after TF operation is set to two. By increasing the number of effective paths from one to two and adaptively adjusting the power and phase difference between the two paths according to the actual channel, the proposed method improves the power gain compared to the ZF-based method and reduces the generation of many undetectable small paths compared to the MMSE method, thus reducing multipath interference. Computer simulations quantitatively show that the proposed method improves the error rate compared to that for the conventional method.