The phase transition behavior of perovskite-type compounds, La_1-xSr_xCrO₃, was investigated by differential scanning calorimetry, measurement of do magnetic property and X-ray diffraction at regulated temperatures. The phase diagram of La_1-xSr_xCrO₃ has been established, which includes four phases, paramagnetic orthorhombic, canted antiferromagnetic orthorhombic, canted antiferromagnetic rhombohedral and paramagnetic rhombohedral. It was also revealed that magnetic properties such as residual magnetization (M_r) and coercive force (H_c) were affected by the variation of crystal structure from orthorhombic to rhombohedral. It was suggested that decrease of deviation of Cr-O-Cr angle from 180° by the structural phase transition decreased Mr and Hc observed in La_1-xSr_xCrO₃ with x larger than 0.11.