Abstract: Using the vacancy-La La_0.77Ca_0.2MnO₃ as matrix materials, Polycrystalline perovskites La_0.71Ca_0.2Sr_0.06MnO₃ have been prepared by the sol-gel method. The reason of large magnetic entropy change was analyzed by phase structures and magnetization curves. The maximum magnetic entropy change of 2.32 J·kg^-1·K^-1 is obtained near its Curie temperature (270.6 K) under the field of 1 T for La_0.71Ca_0.2Sr_0.06MnO₃ sample. The Sample possess stronger cooling ability near room temperature under low magnetic field, and can be used as a good room temperature magnetic refrigeration materials.