Abstract: In order to solve the problem of difficult acquisition of high dynamic binary offset carrier (BOC) signal with first-order Doppler rate in multipath environment, this paper proposes a method based on partial matched filter (PMF) and fractional Fourier transform (FRFT) The acquisition algorithm of high dynamic BOC Signal in multipath environment is proposed. Firstly, the partial matched filter is used to process the signal by segments. Then, the direct signal is determined by using the characteristic of fractional Fourier transform that makes different LFM signals present energy aggregation in different fractional Fourier transform domains. Finally, BOC signal is captured in the optimal fractional Fourier transform domain corresponding to the direct arrival signal. The algorithm can determine the direct signal and suppress the multipath signal except the direct signal. The simulation results show that the algorithm can achieve the acquisition of multipath BOC Signal with first-order Doppler change rate when the signal-to-noise ratio is - 7dB.