Abstract: In order to optimize pump pulse formats of Brillouin optical time-domain analysis based on optical differential parametric amplification (ODPA-BOTDA) and pulse-width difference between Stokes pulse and anti-Stokes pulse, by using perturbation method and small signal approximation, pulse response of probe light with Stokes and anti-Stokes pulses in the small region was obtained. After theoretical analysis and numerical verification of the performances, the results show that Stokes pulse with -phase can effectively compress Brillouin gain spectrum width and increase Brillouin signal-to-noise ratio. Meanwhile, the maximum Brillouin gain is achieved when an optimized pulse-width is 8ns. The study would be helpful for the investigation of ODPA-BOTDA in the subsequent research.