With repetition rate of 1000 Hz, detailed experimental investigation on single large aperture tapered fiber phase conjugation mirror (PCM) has been done. Comparison of stimulated Brillouin scattering (SBS) reflectivity between tapered fibers incised by simple ruby cutter and imported LDC-200 fiber cutter is shown, which implies that the quality of fiber′s end surface plays an important role in enhancing SBS reflectivity. For fibers incised by LDC-200 fiber cutter, comparison of SBS reflectivity with pump pulse widths of 24 ns and 15 ns is also given and maximum SBS reflectivities of 70% and 50% with pump energy about 40 mJ have been achieved respectively. Keeping the pump pulse width to 15 ns and applying the tapered fiber PCM, the double pass output energy, pulse width and beam quality are measured. 1000 Hz, 42 mJ, 1.5 ns laser output has been obtained and obvious beam quality improvement has been observed.