Elasticity modulus is a critical parameter to determine the mechanical characters of the human tissue and materials.The new stimulated Brillouin scattering (SBS) method possesses the unique characters of high speed and resolution. In this study, a SBS measurement system of elasticity modulus has been developed using a passively Q-switched dual-frequency Nd:YAG laser as the source, where two beams acting as pump and pumping lights are employed to generate the seed mode of SBS and then amplify it on ectogenous area, respectively. Thus the frequency shift and line width of SBS can be easily got from heterodyne method. Both the oscillation and output characteristics of the dual-frequency pulse laser have been investigated. The simple and efficient SBS setup allows for the generation and amplification of SBS, which will provide a reference of the application SBS of detecting dynamic change on human tissue and materials in biomechanics and medicine science.