In order to investigate the shear characteristics of salt rock in brine soak environment during the process of salt cavern building, an orthogonal experiment is designed to investigate the influences of brine soak time, temperature and loading rate on the shear properties of salt rock. The experimental results show that: brine soak weakens the shear strength of salt rock, and the longer the brine soak time is, the lower the shear strength of salt rock is, but the shear strength will be stabilized eventually; the increasing of brine temperature exacerbates internal damage of salt rock, which decreases shear strength; the shear strength of salt rock, soaked in a certain temperature brine, decreases with the increasing of loading rate. And the ductile characteristics of salt rock are gradually weakened with the increasing of soak time, temperature and loading rate. The binary linear regression is respectively conducted by any two factors, the relative importance ratio is used to build judgment matrix according to the standardized regression coefficients for salt rock’ shear strength, and weights of various factors are calculated by analytic hierarchy process. The weights of temperature, loading rate and soak time respectively are 0.397, 0.340, and 0.263. The results of range analysis and weights calculation show that the primary factor affecting the shear strength of rock salt is temperature, and the secondary factor is loading rate, followed by the soaking time.