Traditional Brillouin optical time domain reflectometer (BOTDR) generally uses frequency scanning to obtain the Brillouin gain spectrum. And the measurement speed of the sweeping frequency (SF) method is slow, usually on the order of minutes. In this paper, the mechanism of rapid BOTDR measurement based on sloped-assisted (SA) technology is analyzed, the measurement frequency of SA-BOTDR is theoretically calculated, and the system scheme is proposed and designed. Through experimental research, the temperature measurement range of the system is 25°C~70°C at the end of the 203m sensing fiber. The temperature measurement accuracy is 1.38°C, the spatial resolution is 1.21 m, and the measurement frequency is 11.49 Hz.