In the Brillouin Optical Time Domain Analysis (BOTDA) system, different pulse widths correspond to different spatial resolutions, but the Brillouin signals at different pulse widths overlap at the same position. The phenomenon was explained for the first time by pulse subdivision analysis. Based on this phenomenon, a new Brillouin optical time domain localization technique is proposed. Positioning the end point of the strain or temperature segment through two forward and backward measurements can improve the spatial resolution without reducing the pulse width, and overcome the limitation of the pump pulse width on the spatial resolution. And then experimentally verified. 1m long strain segment on a 24,711 m long fiber was localized by 20~100 ns pump pulse with a 10 ns of step. Strain value of 1880 μ with a measurement error of 36 μ was obtained by Lorentz bimodal fitting. Compared with other BOTDA positioning technologies, this technology does not need to reduce the pulse width to improve the spatial resolution, and it is simplicity and effectiveness. The method is believed to have extensive application prospects in distribution sensing fields.