High-repetition-rate and high-stability short-pulse lasers have broad application prospects in large-scale integrated equipment serving industrial manufacturing and scientific research. Pulse compression techniques based on transient stimulated Brillouin scattering (SBS) are an effective means of obtaining short-pulse lasers. The transient effects and thermal breakdown enhancement effects in the high-repetition-rate transient SBS process will cause significant gain attenuation, resulting in a decrease in output energy reflectivity and stability. In this study, we proposed a pulse compression technique based on transient self-pumped Brillouin scattering (SPBS). By combining pump intensity attenuation with gain compensation based on a self-feedback seed model, the transmission loss and sound field intensity fluctuations during scattering were significantly reduced. The experiment verified the compression capability of the transient SPBS, which improved the output energy reflectivity and stability. The results showed that at a repetition rate of 300 Hz, the transient SPBS had a maximum energy reflectivity of 96.5% and an output energy of 24.1 mJ. Without the interference of the breakdown effect, a stable pulsed laser output with an energy relative standard deviation of only 1.42%, a time-domain duration of 225 ps and a peak power of over 100 MW was finally obtained. Our research provides a valuable reference for the generation of high-repetition-rate, high-peak-power lasers.