The invention relates to a stimulated Brillouin gain spectral linewidth narrowing processing, pulse coding and wavelet transform technology-based high-performance rapid Brillouin optical-time domain analysis type (BOTDA) strain measuring device and a data processing method and belongs to the distributed optical fiber sensing technical field. The measuring device is composed of a laser 1, a first optical coupler 2, a first modulator 3, a first microwave signal source 20, a first optical filter 4, a second modulator 5, a second microwave signal source 21, a direct-current power source 22, an optical amplifier 6, a second optical coupler 7, an optical isolator 8, a second modulator 9, a frequency synthesizer 14, a second optical filter 10, a fourth modulator 11, a pulse signal generator 15, a scrambler 12, an optical circulator 13, a sensing optical fiber 19, a photoelectric detector 16, a data acquisition card 17 and a computer 18. According to the measuring device and the data processing method of the invention, three pump signals are adopted to realize optical fiber stimulated Brillouin scattering gain spectral linewidth narrowing processing, and therefore, the precision of a BOTDA strain measurement system can be improved; pulse encoding and wavelet transform technology are combined to improve a signal-to-noise ratio, and therefore, measurement accuracy can be improved, and measurement time can be shortened.