Abstract：Reducing effects of limestone strength on the unconfined compressive strength of limestone are studied according to acid-rock reaction experiments of the static high temperature and the rock compressive strength tests，and analyzed stress-strain curve and mechanics of damage for limestone. Test results indicate that after reaction with the same gelled acid used on the test，elastic modulus highly decreased and Poisson¢s ratio increased a little，unconfined strength are about 20% compared with the same parts of limestone before acidized. During the acid-rock reaction，difference of reaction rate and acid etched pattern are obvious between matrix limestone with fractural limestone. Reaction with the same gelled acid used on the test，the reaction rate of Tazhong fractured limestone is about two times of Lungu matrix limestone. The etched pattern of fractured limes is local and deep，the matrix limestone is superficial and symmetrical. Different limestone pattern determined different etched pattern，and together with acid system，different etched patterns resulted in different strength reducing effects of limestone near fracture area during acid fracturing. The research results can provide effective technical parameters for designing and optimizing of acid fracturing.
