According to the requirements of the sensing distance and signal detection for the Brillouin optical time domain reflectometry (BOTDR) sensing system, a hybrid G-Simplex coding technology is proposed based on Simplex code and Golay code. The BOTDR signal is processed by combining the G- Simplex coding with the average superposition algorithm. The results demonstrate that this method can keep the space resolution. The signal-to-noise ratio and sensing distance is improved by using a certain code length. Moreover, with the same denoising effect, the intensity of impulse response can be improved and the superposition times can be largely decreased, which reduce the difficulty of weak signal detection.